I think most of the people who pick blue would be empathic, loving people that are just kind of bad at game theory.

I don't think I want to live in a world in which they all died out.

Yes, the selfish-minded would end up with more selfish-minded people, and they'd be confused why their "low trust society" became even more low trust overnight.

Yes and yes. Without the core of blue workers, red people will need to open Atlas Shrugged about how to assign short order cook duty.