The operative question is if Joe Biden being too old weakens the chance to save democracy.
If you say no, that's your call. A lot of people are really worried it will guarantee a loss.
There's no "the chance." It's us. Us who need to either rally around him *now* or hand it to Kamala *now*, but thinking about it in terms with no agency (ie if it's "his age" that will lose it) encourages endless rounds of trying to craft a scenario, rather than showing up, armed, to the fight.