Housing is cheaper in other places because salaries are lower. The same worker who is paid enough for a $600k house in a tech hub would be paid proportionally less in a place with cheaper housing. (Unless he was just underpaid in the tech hub, and could have gotten enough for a palatial house in the tech hub at a different employer).

People don't live in the national average, they live in limited geographic areas, and the salaries that make people try to characterize tech workers as rich tend to come in - you guessed it - SF, NY, and DC.

That's not quite right: you only get your whole surplus extracted as rent in a market with artificial restrictions on housing. Unfortunately for us programmers our top job market happens to be an awful housing market, but that seems to be an accident of history -- we could've ended up somewhere else with rents that are high but not ridiculous. That's how Bay Area rents seemed to me 15 years ago.

$600k is about 1500 sq ft, where I live, while median US home size is somewhere in the mid-2000's of square footage. Maybe when I'm house hunting, I should point out that I could get the same thing elsewhere for $200k.