I just want to comment that the trend where "average" workers pushing 50 are undesirable, is a very scary one. And it should be for everyone.
Any present day 45-year old must assume that they will have to work AT LEAST 20 more years, but most likely 25. This generation will be working well into their 70s.
Statistically, the majority will be average - or "mediocre".
Economically, it is very unsustainable to have a system where only the top 20%-30% of people over 50 will be able to keep their job. You'll end up with a very large number of people that end up on welfare, or unable to spend money like the modern society is designed (less spending, less revenue for companies).
I wonder if the heavy ageism was more a one time thing. The entire tech industry blew up in the late 90s early 2000s and all of a sudden 20 year olds were handed endless VC money, of course they biased towards people their age when hiring. That isn't going to happen again, the huge players are established and founders are generally older. I started in 2012 and the same people who hired me when I was 20 are still around and are going to naturally bias towards people in their own range.
If anything I predict the ageism will be against young people, where anyone who got significant experience from 2000-2020 will be desired because they worked through those foundational years and never leveraged AI. Meanwhile a 22 year old who scraped through a CS degree will be viewed a bit dubiously.