The problem is that it happens in little cliques of 2-3 people, and it's hard to meet a new clique. (I mostly do intoxicated at parties.)
I've been thinking of trying to organize "Work in Chalk" parties or something next summer, where we can all go hang out and work on our theories in sidewalk chalk at the park. (I used to do homework this way in uni.)
It's just hard to guage how many people would be interested and how to reach them.
1. There's a fine line between open-minded and irrational, and unfortunately a lot of people end up crossing it. This becomes a negative feedback loop wherein more and more people don't want to risk their reputations by sounding like they identify with irrational / fringe groups or ideas.
2. It's easy to identify genius in retrospect, but prior to being validated, people who really think ahead of their time are by definition in the minority, so they either have to get used to being laughed at / criticized, or give up. So I guess I would say, keep looking for peers who are open-minded but not irrational. I went to Carnegie-Mellon (`03) and knew hundreds of bright people there, but only 1 or 2 who I considered to be able to think out of the box, as you say. They're people worth finding, though!
Also, HN in particular can have a kneejerk objectivist flavour that discourages intuitive, unconventional discussion. Dismissing people who seem irrational is not a good way to encourage healthy cognitive diversity, and we could do with less of it.
The point I was making was that those people do a disservice to open discussion because nobody wants to be painted with that brush, so it ends up becoming an HN-type situation where, as you rightly pointed out, there is a resistance to new ideas. There's probably a formal-discourse type term for it.
Then I switched to the computer industry when I finished my studies, and the atmosphere suddenly changed.