Will yet another addition to the countless store of existing stories on Biden being 3 1/2 years older than Trump will a competitive primary into existence?
By 
Phillipsmentum!
The question answers itself, which is why some commentators are denying that the countless Biden age stories exist:
What’s interesting is Dean Phillips just gave us a field test of “what if you could run some random normal Democrat who’s younger than Joe Biden” and it did not exactly take the world by storm.— Matthew Yglesias (@mattyglesias) February 4, 2024
On the empirical question here, the idea that the media is refusing to run stories about Biden’s age is Alice in Wonderland stuff. It’s about as under-covered as stories about Hillary Clinton’s compliance with email server management best practices. Reasonable people can disagree about whether this level of coverage is appropriate, but a lack of media attention to Biden’s age is not why Johnny and Jane Unbeatable haven’t run in the Democratic primaries.
The second revealed-preferences point is also critical. For all this talk about “bubbles,” etc., at some point commentators who insist that it’s many ordinary voters and not them who consider Biden’s age a dealbreaker have to address why this allegedly widespread Anybody But Biden sentiment can’t crack 4% in the South Carolina primary. Granted, Biden’s opposition in 2024 is the definition of “nominal” (which of course raises questions about why ambitious politicians with actual potential have refused to shoot this purported lay-up.) But if age is hugely important to voters, I ask again how, in a huge field with a lot of younger candidates who at various times were considered potent challengers, candidates over the age of 70 got 92.6% of the vote in the 2020 primaries?
Look, all things being equal I would also prefer a younger nominee. If I were given unilateral authority to choose the Democratic nominee — and I certainly should be! — I would pick someone like Gretchen Whitmer. But it’s a useless discussion. Democratic voters are very aware of Biden’s age and if there are is a substantial group of people for whom it’s a high priority apparently they never vote. The Democratic nomination for 2024 is a settled question. There’s nothing the political press can do to change this. What they can do is make it more likely for the 77-year-old and unfit-in-every-possible-respect to win by running an endless parade of redundant stories about his opponent’s age.