I would add Robert Duvall to your otherwise good list. I have yet to see him in a bad movie.
Apocalypse Now ring a bell? His performance in it was great, the score as well; but the film was trash.
Duvall and Hackman are the two premiere “older” movie actors in America. Mine was a very hasty list, and I was just considering the real old -timers.I meant to add Cagney and Edward G. also.