A lot of them don't actually know that.
Every time someone posts one of those developer salary articles here, from levels.fyi or similar sites, there a long line of naysayers who just can't believe the numbers are real -- but they are real.
The question really flips when you ask yourself, how much could someone pay me to only visit my family only once a year?
I agree that getting a job there is not very hard. Getting a senior role (which is what you originally mentioned) is. Anyone who is more than a few years out of school either needs to be really good or accept taking a significant step backwards in career progression (and probably a lowballed comp package).
FWIW, before I joined my company (a FAANG), I was an engineering manager/tech lead hybrid. I ended up as a high mid-level in pay band, but being paid at just below the average of the next band up from numbers I've seen around, and currently grew it to more than most at the senior level. I may have taken two steps back on the career ladder, but I've almost tripled my compensation (in large part due to stock performance) from my startup job 3 years ago (which was already pretty high for the market for my background), and I have even more freedom in most aspects with what I get to work on & a very strong management team that supports me.