I didn't mean to suggest that no one realized it was helpful to be surrounded by a lot of people working on the same things. I've written about it a couple times myself. The surprises for me were in the details. E.g. that with startups, people are more willing to help out their peers than in more zero sum fields, and that you need that extra margin of help because startups fail by default.
"that with startups, people are more willing to help out their peers"
I'm going to guess that this happens in the entertainment industry as well. The similarity being that the person you are rooming with or working with who has a bit part on some show with you might be the next big star. So I would imagine people tend to be nice and helpful to people in any field where there is a big prize and it's not easy to tell (like with sports) who the next star or Spielberg might be. Because in addition to skill (which many have, as has been said with acting for example) there is luck and landing that key opportunity that launches your career. And if you happen to have known or have been friends with that successful person it could only help your career.
