What, what, what if we always were a gerontocracy but people used to die earlier and people used to die before dementia got them. So more common & more problematic.
I'm thinking in particular of Harrison Ford/Han Solo's career. As long as he not dead and in the pile of resumes, directors will keep casting him for new shows. (Just wait for Chewie & Hans Pre-Last-Jedi Adventures on Disney+)
Life expectancy in the US for men was 58 in 1930 vs 79 now.