The guy who decompiles third party code at 4 am to see why their update caused an error in our system (real recent story).
The other (very competent) older people get actively harassed. Some little *es from my company tried to get an older guy fired for being "too slow", when he is anything but. And I think the company I work for now is one of the friendlier environments for older devs.
Dunno, it's a genuinely scary prospect. Not trying to put anyone down, just what I see around me.
I hear its even worse on the coasts. I am in a flyover and have never worked in San Fran.