Even if Trump isn't as sharp as he was 8 years ago
He wasn't sharp then either.
the public perception that Biden is doddering is already baked.
Among the desperate victims of the conservative projection machine, sure.
"Trump isn't senile! Biden is!"
"Trump isn't corrupt! Biden is!"
"Trump isn't a wannabe dictator! Biden is!"
"Trump isn't out of his depth! Biden is!"
Biden's age registers as a significant concern for voters. Sorry that's inconvenient for your team! haha
Yes. And it’s not glossed over both because it’s true, and because the liberal/centrist media tries to both-sides things. The more left-wing media have never liked Biden either so they’re not inclined to do things that might help him, and Democrats in general have a lot of younger voters who, even aside from Gaza, really don’t like that the choice is between the same old white guys as in 2020.
Meanwhile, right-wing media pretends that Trump is incredibly smart and high-functioning because they’re too cowardly to oppose their audience, ie. the people they’ve cultivated and egged on for decades, and also because they think Trump will reward them for it (which he very well might—temporarily). The Republican Party is at war with reality and doesn’t play by any rules, so it’s not exactly a fair fight.