Blunt tools shouldn’t be used for complex real-world things. Other examples would be mandatory sentencing in courts (you should let the judge assess the particular situation), or things like “I don’t go out with guys under 160cm” (you should get to know him).
Just because someone is in their 70s, doesn’t mean they can’t lead. Not with any certainty. In some cases it does, but the political process should have the flexibility to deal with each case.
Look at Deng: he was mid-70s to mid-80s when he was in power and he improved the lives of 10⁸ or 10⁹ people.
So a couple of things.
I generally think all the “Biden is so old!” stuff is pretty silly. The president largely delegates. Yes he makes tons of decisions and some of them must happen quickly. But generally, I do think the president can be an elder.
However. Contrast this with members of Congress. They sit on committees. They have to learn intricate details about the committee topic. They are supposed to pass laws to keep our government current (and then largely the president appoints leaders to execute those laws passed)
Overall, it would be great to have more Gen X and Millenials in office. Specific leadership roles can be filled by the old, as the old folks do gain some things. But when leaders refuse to engage on new topics or refuse to understand why 90% of people under 50 all agree on something… That’s a problem.