We're good at most things as long as it doesn't involve too much interaction with people. Customer service is bad, sales is bad, etc.
I think the most important thing for us is variety with not too much nuisance interaction. Apparently being a university professor is a common choice. I may try to go that route, but I'm yet to overcome my fear of talking in front of large audiences...
A lot of MBTI websites recommend being an outdoors person, like a park ranger or outdoor adventure guide. I could easily see myself doing that. Even if I were doing similar activities each day, the feel of being outside would be all the 'variety' I needed. The good thing about it would be the relative autonomy. Same goes for being a photographer.
As far as our true value in a perfectly executed society, we certainly are the thinkers, philosophers, and general solvers of complex problems. But unfortunately is society isn't perfect, so we have to abide to a fucked up system where 95% of the population don't get to make use of their real potential. It's not just INTPs who are thrown on the pile.
I personally have made the choice to do whatever shit (or good) job I can find, and in my free time do what I enjoy or am good at. That way, maybe some day the two sides will merge and I'll end up in one of those lives where every day is a joy. The problem these days is that people don't want to grow or push themselves for what they want. Everyone just goes to their shit job then sits at home complaining that they think they deserve better. I'm in South Korea at the moment and have learned a serous nugget of wisdom from their culture. Laziness is thoroughly disapproved of here. In their free time, Koreans actively do the things they want, whether it's to better their future or for the joy of doing it. So I'm trying to take a leaf from their book. Work might be shit, but the future is always bright, as long as I aim for it. (Which in my case means joyful amounts of self-study in my free time, which I seem to enjoy far more than I could have ever expected).