The reality is that, so far, there's little polling evidence that Biden's lost much support since the debate. But that's not gonna permeate the bluesky ecosystem because election/polling twitter didn't migrate over here.
More importantly to what they are trying to push, there isn't anyone who wants the job that is doing _better_ (I think, Michelle Obama polled better, but, IIRC, she practically laughed at the idea of running)