Okay I think this makes sense to me, theoretically and in terms of my ENFJs. One more question, when you refer to self-preservation, are you referring to the ENFJ's need?
Have you ever found your 'deep' friends becoming exhausted by your intensity?
ENFJs do have to respect other people's need to self-preserve, but the ENFJ need is strong due to how clouded our ability to help ourselves can be. If others demand of us, we'll put ourselves on the backburner, unless we've already learned not to.
I've mainly dealt with a lot of people who wanted my time and advice, but couldn't recognize what time I needed for myself.
My closest friends have definitely been exhausted every now and then. I can easily dominate conversation and mood, but I'll feel it out a good deal and adjust accordingly.
I have an ENFJ friend who is excessively intense, very sensitive, doesn't have self-awareness, and doesn't respect self-preservation. She's going to have a lot more trouble when it comes to deep relationships because of those things.
This is where ENFJs have to learn to be more aware of themselves and how much they are taking from someone when given the chance.
Amusingly enough, my closest friendships now are with xNFPs. We're of the same NF family, but still quite opposite. There's always a lot to learn from and teach one another. A good relationship between the pair will be open enough to say "You are putting too much forward" or "You are holding too much back"