Agree with your sentiment. To add to it: I was just in Longmont, a town 45 minutes north of Denver, where Seagate, Western Digital, and San Disk all had major presence. Definitely not a big city.
Tech has enabled us to live anywhere and do our jobs.
I think there's this thread of people who live (and want to live) in very high CoL cities feeling the need to justify it to themselves and others on the grounds that they have no choice if they want to have a successful career.
Part of the problem is that you only get one real crack at the career game. As you get older, your options diminish and the negative social inferences that come with age (even though they have no basis) tend to mount, so you don't have a lot of chances.
Bosses definitely pick their successors based on the "one of us" metric, much more than actual merit or job performance, and this usually means one has to live in the same expensive neighborhoods and send one's kids to the same expensive schools as theirs. Is it possible to succeed, without playing that game? Yes, of course. However, it's unlikely, and so I wouldn't bet my life on it.
That is complete BS. Certainly it is among the tech people I know. Furthermore, even those tech offices that are in the orbit of certain cities often aren't in those cities and are located in, not cheap, but pretty reasonably priced areas outside.