If Kamala Harris is already Vice President, what is the advantage of dropping Biden to run her? She already takes over if he can't do the job. Is her Veep pick going to bring something to the table that isn't already there? I legit don't get why we want to choose chaos 4 months before the election.
Biden resigning to elevate Harris would be a political disaster. Dems would lose the tie-breaking vote in the Senate, as well as oversight of the electoral college certification. The GOP would block anyone Harris nominates as VP, so Mike Johnson would be her successor. Imagine what comes next…
I haven't done check, but I suspect that many of the people who don't want Biden now are the people who didn't want Biden before. (I.e., the subpar debate performance is a pretext for what they wanted anyway.)