I know a lot of both, and you usually have to know or watch them for a long time to recognize that they are in fact very similar in what they're doing. It's easy and simple to think that they're so different they could never have anything in common. I also always noticed that people gravitate to the E and leave behind the I, almost all all the time, thinking they're more capable or smarter!
It's only stupid people and kids. The rest of us realize a meaningful person vs. a loser, regardless of whether it's an E or an I. We know what makes a successful/decent person and what doesn't, regardless of what someone says they are, and how they act like they are. Kids alot of times buy the bullshit, whereas, many older people have been there, saw, and done that. Stupid people, however, will buy it forever. Kids seem to think the grass is greener with an E, because they work to make it appear that the grass is greener. It's not so.
Self-confidence and bullshit can take you a long way in this world, with stupid people only. Fortunately, people who thrive on bullshitting their way through life have to pay. At some point, an I usually realizes what they want to be, is an I, and anyone who falls for, "E" is smarter and better, has their own set of problems to overcome. It's one good way to filter out the stupid, the frivolous, the losers, and the immature, and keep the "gems".
I have found that in the case of istp and estp specifically, an estp will accept a lot more people than I will. I don't want them in my life, whereas, they think said-people are okay. Some istp's can be extraordinarily picky about the company they keep. So they are choosing to be "left-behind" as you call it...... I call it being selective with my friends and activities. I think estp's can be much more welcoming and accepting, and that makes people feel more comfortable with them, whereas, I am always calculating and wondering what said-person is up to.... and they can sense that. Istp's don't love people like estp's can. If they don't pass the test, they aren't welcome in my life, and that happens magnificently easy lol.

It's all in who you are and what your interests are.... and I can be extremely exclusionary when it comes to my own inner-circle, private, and I want to separate myself from others. People know that. It's not necessarily that they think an estp is more capable or smarter; it's that they are welcoming and they are entertaining. Some estp's just make people feel good, and they can be a lot of fun. I lived with one for 22 years (my father), and to me, he was nothing but one big pain-in-the-ass, but I loved him.

I used to come home and there would be jehovah's witnesses in my living room talking to my dad, and I would think, "wtf is he thinking?!" lolol...... He just wanted someone to entertain.