I'm just presenting a model, and I'm not saying it's perfect. My model allows me to integrate a bunch of disparate elements and see them working together as a cohesive whole. But take it with a grain of salt. It's just me playing around with some ideas. Someone else could present another model or improve on my model.
(The following is a long post. If you don't want to read the entire thing, you can skip down to the second set of asterisks and read the summing up. That'll give you the gist.)
Traditional Freudian psychology says that as children we all undergo individuation (splitting off from our parents and developing our own identity), and subsequently we seek ways to influence our environment in order to achieve our own desires. Since our parents are the main ones able to deliver us what we want, this process largely comes down to a contract we develop with our primary caretaker. The child effectively says to the parent, "I will behave in X manner, and you will be amused/impressed/grateful enough to provide me what I want in return (usually love and approbation)."
Again, Freudian theory says that having found the behavior X to be a successful way of getting what we want, we tend to perfect it and use it as our main way of dealing with people right up into adulthood. From this, you get the Freudian truism that in our adult relationships we are just playing out the conflicts and dynamics that we developed as children with our parents. You also get the truism that dysfunctional relationship dynamics (a flawed or unhealthy X behavior) have their roots in the childhood environment. For example, traditional psychology tends to hold that personality disorders originate with a dysfunctional environment and dynamics in childhood.
That's all pretty standard stuff, and none of it necessarily conflicts with traditional Jungian MBTI theory. It just raises the assumption that to some extent we "chose" our personality type functions because they worked or were favored in the our relationship with caregivers and our general childhood environment. (and/or were a best match with our natural talents).
Thus one might look at the 16 MBTI behaviors/beliefs/value systems as 16 different contracts with the world: "I will provide product/behavior X, and you will respect and love me."
Of course, depending on the personality type, "providing product/behavior X" can mean a lot of different things: "I will entertain you by being funny;" "I will protect you from disorder by providing you with a clean and organized household"; "I will fascinate you with my technical/mechanical/athletic/intellectual/oratorical prowess"; "I will give you pleasure by servicing your physical needs"; "I will protect you from fear and doubt by being super-competent and always having solutions to all your problems;" and so on.
A couple themes keep popping up, for example offers of protection, offers of entertainment, etc. These reflect the deals we made with our parents and the things that earned us the greatest rewards in childhood (and/or were a best match with our natural talents).
In addition, a couple other sub-themes pop up. For example, some behavior or products are interactive and hands-on: I will provide a certain environment or certain services for you (I will be a good homemaker, I will service your needs, I will protect you from dangers and fears). Others are more solipsist and mostly concern display and entertainment: I will fish around inside of me, pull something out of my butt, and attract your attention: I will amuse you, I will provide art for you, I will create weighty thoughts for you. The athlete, artist, comedian, philosopher, and moralist fall into the latter category. Obviously the INFP idealist falls into this category as well.
The athlete, artist, comedian, philosopher, and moralist detach themselves from the audience, create distance between themselves and the audience by climbing up on a stage, and they say to the audience, "Watch me, I will entertain you!" (Let's call these people "actors," since that's really what they are.) Again, it's the reenactment of the old childhood contract with the parent: "I will behave in X manner, and you will be amused/impressed/grateful enough to provide me what I want in return (usually love and approbation)."
If the entertainment is successful, the audience will applaud and approve the entertainment, and the contract will be successful for the actor. If the entertainment is a failure, the audience will boo, the actor will tell himself that the audience doesn't recognize true art, and either he will work on his act to improve it or he will refuse to have anything to do with the audience again. In the latter case, he'll insist that he loves the art and the stage and the audience, but he'll refuse to have anything to do with any of them because the audience isn't good enough for him.
The degree of one's solipsism affects the chances of one's success. Good actors avoid the trap of solipsism; they pay attention to their audience, interact with it, figure out what the audience wants to see, and improve their act to better deliver what the audience wants. These are your successful athletes, artists, comedians, philosophers, and moralists. They honor the old saying: "Know your audience."
Bad actors, on the other hand, are often too solipsist to really pay attention to the audience. They see themselves as the center of the world; the audience is only an indiscriminate mass beyond the footlights. Solipsist actors care only about what's inside them and what they themselves are feeling; it doesn't matter what the audience wants. In the heat of performance, the solipsist actor may be so focused on being true to himself that he barely registers the audience. He may see the audience as little more than a mirror in which he watches himself.
And when the audience gets bored and registers its disapproval by booing, the negative feedback can be crushing to the solipsist actor. At the end of the performance, the solipsist actor still needs the audience's approval; after all, that's what this whole exercise is about. The audience may only be a mere mirror to the solipsist actor, but mirrors have the power to make us feel good or feel bad. If the audience reflects back a negative image of the actor, the actor may be too crushed to ever act again. He may break the mirror and reject the audience forever.
I've mentioned in another thread that I see the INFP mindset as potentially highly solipsist. Many INFPs rummage around inside themselves (fantasy worlds, childhood memories) for emotional experiences. It can give them an inward, self-involved orientation.
Furthermore, the occupation of moralist and idealist can be one of the most difficult and least rewarding. When an idealist gets on the stage and harangues the audience about how they don't measure up to his ideals, it's easy to lose the audience and get bad feedback.
Effective idealists who interact successfully with an audience can, in fact, earn the highest praise and respect: They are accorded the title of "prophet" or "revolutionary". But that requires a high degree of skill and ability to interact with the audience. Most idealists are too solipsist and self-involved to interact effectively with the audience. They are usually pulling their morals from inside, and they forget to account for how the morals will be received by the audience.
So the audience gets tired of being harangued and starts booing, and the idealist is chased from the stage. The idealist takes this negative experience as one more proof that the audience is unworthy of him (can't live up to his high ideals), and rather than learn from the experience about the need to interact successfully with the audience and fit his message to the audience, the disillusioned idealist goes off into the desert to play the role of "voice in the wilderness"; meantime, the audience turns its attention to the next actor on the stage.
To sum up:
One's interactions with the world around them tend to follow (in some manner or other) the model of a childhood contract with the parent: "I will behave in X manner, and you will be amused/impressed/grateful enough to provide me what I want in return (usually love and approbation)."
As they grow up, some people become increasingly solipsist. Their act (the behavior X) may become increasingly important to them. If their act becomes all-important to them and they cease interacting with their audience (their spouse, their workplace, the society around them) and/or they cease accepting corrective feedback needed to keep the audience engaged, then they may find themselves isolated and alone: A lone voice in the wilderness.
INFPs tend to be solipsist by nature (seeking emotional experiences from inside) and also by calling (the message of the moralist and idealist comes from inside and is not an easy one to sell to an audience). A few INFPs manage to bridge the gap between their message and the audience and are acclaimed prophets and healers and revolutionaries. But most INFPs don't. And being too solipsist to learn from their experience, they end up rejecting their audience (their spouse, their workplace, the society around them) and find themselves alone.
They break the mirror, reject the audience, and go off alone. They still insist that they love the audience (like everyone else, they still want to act out the childhood contract with the audience), but interactions with an immoral (unappreciative) audience are too painful.
Of course, there is a simple solution. The audience need only approve the INFP. The approval may be insincere, but many INFPs are too solipsist and self-involved to notice the insincerity. And with time and patience, the INFP can be induced to pay more attention to the audience and incorporate feedback. And after all, the central message of this whole thread (at least my part of it) is accepting people as they are. The INFP deserves that acceptance too, as flawed as he may be.
Also, some of you other types may want to consider how your "act" (the behavior X) may be separating you from your "audience" and isolating you.
Again, take this message with a grain of salt. I'm just theorizing and playing around. Please note that there's a tongue-in-cheek (INFP hyperbole) element to this message, as always.
Also, the post is overlong and could be condensed and made more effective with a rewrite. But the wife and I are headed out dancing, and I figure I'll send the post off as is. Remember the nature of INFPs: A little insincere approval from the audience is a good thing and a sign of acceptance of people as they are.