But at age 90, it's something like a 1 in 4 chance you'll die every year. So, even if he's only 9 years older than Stewart, the odds of him outliving Stewart would have been pretty low, all other things being equal.

Its more that he has out lasted the TOS crew. If he goes after George then I know for sure some dark arts are a foot.

It is crazy how TNG feels much more recent.

Somewhat related, it's also crazy that Rosalind Chao (Keiko O'Brien on TNG) played Soon-Lee on MASH (the woman who marries Klinger). MASH and TNG feel absolutely eons apart, but in real life they were within ≈4 years of each other.

They were still making TOS movies while TNG was airing