SF is an extreme but most of the high paying tech jobs cluster in areas which are closer to that cost of living - doing well, sure, but far from rich and definitely not able to count on being set for life since one illness, untimely layoff, etc. can easily derail a career.
That’s not to say that there aren’t ways to economize but there’s a long history of lazy editorializing about how kids these days are spending too much on avocado toast while studiously ignoring the data showing that the big problems are healthcare, housing, student loans, etc.
You can save a shitload of money in Iowa making $95k/yr.
https://www.bls.gov/oes/current/oes151251.htm#st
Again, note that I’m not saying you can’t make a good living elsewhere - having spent the first 15 years of my career doing that, it’d be odd - but that it’s not a simple ticket to being rich or even especially upper middle class. The pay scales definitely drag down, there are fewer jobs (and thus promotion opportunities), and they’re concentrated in the higher cost areas of low cost states.
Still solid, no question, but not a gold ticket. Note that many of the things the person I originally responded to are expenses which don’t scale down: if you live in a rural area your house is cheap but the two cars your family needs cost the same, computers and other consumer goods are only slightly less, etc. Those private schools are cheaper but not dramatically so, etc.
This is also true of developers in the US. The number of lucky ones who can retire significantly early is a tiny fraction of the market — but companies have very successfully used those dreams to get lots of free overtime from people who didn’t notice where most of the money ends up. FAANG developers do well but even there early retirement is not a reliable plan.