Switch to where? There are hardly any 6 figure professions out there that don’t require a significant amount of training and sacrifice in the early years.

Doesn't matter. They lived in the golden age, they had a long time to buy their house when they were much more affordable. They have no renting problem.

Not to mention that apple pays well and has good benefits, so they are not sacrificing anything by staying, quite the opposite.

I worked on the core audio team. It’s kind of hard to find another company that pays as well as Apple where you get to continue doing that kind of work. The only other companies I can think of are either lab126 (Amazon) or google. Lab126 doesn’t pay as well as Apple.

Also, apples 401k match and internal stock discounts are amazing.

This isn't unique to tech. My father has almost 40 years in medicine and his salary hasn't gone up beyond inflation/cost of living in at least 20 years.

Because most of them can't. Only so many of senior engineers can become managers (because of obvious mathematics, management is a much smaller fraction of overall jobs available). Most of them get to a point their salaries flatten out and there isn't any advancement they can do. At that point that usually have paid off mortgage and kids so they are content just having better work life balance, doing 9-5 work & collecting their paycheck, not caring too much about advancing from that sweet spot.