It's not that they MUST live in the most expensive city. Rather, they MUST live with (and work) the most bright minds. That creates a geographic pooling problem.
I don't think that's an entirely dismissible goal, by the way. Humans are social beings and more often than not we're better off working with other smart people. Collaboration of bright minds is responsible for some of the incredible achievements of humanity.
Clearly if the likes of some of the biggest, and most successful tech companies in the world are located in the bay area, that might be proof enough that some pretty impressive minds reside there? I'm merely making the point that IF one wanted to work with like minded, smart people, moving to the bay is one way to maximize your chance of finding said people. I think we could both agree you're less likely to find them in Nebraska, though of course there are some very talented people there as well.
Furthermore, who is being arrogant here? The person who wants to live in and among bright minds, or the person who denies the bright minds exist? Takes a pretty arrogant person to deny that there's a lot of talent in the bay.
https://www.newyorker.com/magazine/2002/07/22/the-talent-myt...