Some of the best people I've worked with are those who've been with the company for a long time. IME, the dead weight tends to be phased out over the years, so there's a bit of survivorship bias with the remaining ones.
However, the road certainly isn't easy for them. Despite the utility of these people being totally obvious to anyone whose ever worked with them, with each change of leadership comes another fight to keep their jobs.
The one that stuck with me was when I worked for one of the biggest companies in the world, and they laid off the man who had more patents than anyone else in the company, by a good margin. He was in his late 50s, and he came onboard after getting his Ph.D, leaving once to found a startup, which was acquired by the company after a few years. He was brilliant, humble and could have absolutely been a professor at MIT or a principal at Google. But he loved working for our company.
That's not ageism though. Getting pushed out because they lost the shelter of their patron(s) or because they were on the losing side of a political battle, which is a common cause of the departure of people like that, is a different thing entirely.
However, the road certainly isn't easy for them. Despite the utility of these people being totally obvious to anyone whose ever worked with them, with each change of leadership comes another fight to keep their jobs.
The one that stuck with me was when I worked for one of the biggest companies in the world, and they laid off the man who had more patents than anyone else in the company, by a good margin. He was in his late 50s, and he came onboard after getting his Ph.D, leaving once to found a startup, which was acquired by the company after a few years. He was brilliant, humble and could have absolutely been a professor at MIT or a principal at Google. But he loved working for our company.
I got the hell out of Dodge after that.