There seems to be a popular view nowadays that most old people grow to be senile (just look at any online discussion of old politicians for example). This is not the case!

Sad as it is, when stars from classic Hollywood stop being visible but are still known to be alive at a highly advanced age, dementia is often the case. Gene Hackman, Gene Wilder, and Jack Nicholson are notable cases, and I just assumed Beatty was similar.