5 of those presidents were elected twice, and one wasn’t elected at all.

For the non-Americans or those just not up on Presidential history: Ford was the one who never got elected.

Nixon's VP -- who ran with Nixon and got elected in '72 -- was Sprio Agnew, who later resigned due to corruption allegations. Ford replaced Agnew, and then replaced Nixon when he got nailed by Watergate.

Brilliant maneuvering? Or falling bass-ackwards into the Oval Office?

Yes, so using that method and excluding Gerald Ford it would be the age of George W. Bush when he was re-elected, so about 59 years old.

  Clinton 46 years 154 days
  Clinton second term
  Obama 47 years 169 days
  Obama second term
  Carter 52 years 111 days
  Bush Jr 54 years 198 days
  Bush Jr second term
  Johnson 55 years 87 days
  Johnson second term
  Nixon 56 years 11 days
  Nixon second term
  Bush Sr 64 years 222 days
  Reagan 69 years 349 days
  Reagan second term
  Trump 70 years 220 days

Nevertheless, I wouldn't use the term "old age" regarding any of these presidents, with the exceptions of Reagan and Trump.

Here's my point. The author of the article wrote: "One possibility is that it’s mere randomness. It’s only one election that’s been roiled by Trump, you might think, and younger blood is waiting in the wings."

I believe this is the mostly the correct answer. No, it has nothing to do with Trump, but, yes, it is just randomness. Younger blood will come again the future, as it has in the past. I'm not convinced by any of the proposed arguments to try to prove the opposite.

Just one example, "Older politicians have had longer to build up donor networks, and older rich people may be more likely to take the risk of self-funding. If Jeff Bezos had quit Amazon to run for president this year, he would have given up years of peak earning and peak productivity in the private sector."

Sure, that's true, but that didn't stop, for example, Clinton or Obama from getting elected long before they were old, because there are many other factors at play other than those mentioned above by the writer.

Briefly, there's no way to know now who will be the candidates in the 2024 American election and how old they'll be.

Edit: Typo 2024, not 2026

I messed up in the above message when calculating the median:

  Clinton 46 years 154 days
  Obama 47 years 169 days
  Clinton second term
  Obama second term
  Carter 52 years 111 days
  Bush Jr 54 years 198 days
  Johnson 55 years 87 days
  Nixon 56 years 11 days
  Bush Jr 58 years 198 days
  Johnson second term
  Nixon second term
  Bush Sr 64 years 222 days
  Reagan 69 years 349 days
  Trump 70 years 220 days
  Reagan second term

The median is the age of Johnson, 1st term, 55 years 87 days

Plus I can’t count. The median is the age of Nixon, 56 years 11 days.

Serves me right for not taking enough time to check what I write before posting. Lesson learned.

My bad, 2028, not 2024 or 2026.