Also - I read about Shel Kaphan the other day - employee #1 at Amazon - he must have been in his 40s when he started there if he was studying in 1975. Obviously his age didn't deter Jeff Bezos.
I've worked in places where older employees become irrelevant to the business because they get stuck in their ways and don't want to / can't change. If you're not prepared to re-skill, or you think your job is safe - you're in for a rough time if someone else controls your destiny. That's not to say people don't get badly treated by organisations - they do, and that's wrong. But still, working life is a struggle and a balancing act.