The amount of new grads and people coming in from other trades because they want a piece of the cake is high enough to keep supporting the flywheel. It would be interesting to see median age of engineers at tech companies, here it's definitely well under 35.

Anecdotally, I see some people in their 40s or early 50s who made very serious money and worked really hard (founders, CEOs, and the like) end up doing some of the on-the-side type of work that gets thrown at people in that position (boards, "advisors," and the like). But I don't actually see a huge number of late career regular employees (even fairly well-compensated ones) retiring way early.