In the 80s, the Soviet Union was criticized for being a gerontocracy. Brezhnev came to power in his 50s, and died in charge at 75. He was replaced by Andropov, 67. Then came Chernenko, 72. They had worse medicine than we have today, but they would all be spring chickens compared to our recent presidential candidates. The median US senator is 65. Chuck Grassley is 89, and has held his seat since 1981. Diane Feinstein is also 89.

And the picture in the Supreme Court isn't much better, even though there are big advantages in nominating young judges, which can hold on to their seats for many decades.

So is the US a gerontocracy? It's not much of question.

In case you didn't click through, the wikipedia article has a whole section about the US.

Trump, Bush, and Clinton were all born in 1946 (ie pure baby boomers). But Clinton was a much younger president than Bush, who was a much younger president than Trump.

I think Clinton was younger than Obama when he took office.

The Senate is 79% Boomers or older, too.