Every voting person would know within a week if Biden stepped down and gave 1/4th the support to the new candidate what he gives to Israel’s far right wing government.
My naive theory is that Biden plans to drop out as late as possible so that he can take a media beating from the Republicunts and protect the real DNC nominee.
When the DNC "upset" happens, there will be coverage. All the people with half a brain will be relieved and vote blue. Fox will fire up propaganda, but it can't compare to years of "Biden bad"