The Dems don't have to be in disarray. They can show they are a party that is able to make the right decisions in crucial moments, for the country. They should have done that first by Biden not running again in the first place. They were warned by plenty of this was a terrible idea and gamble. Dems are too timid, too afraid to rock the boat, message better - it's a fundamental flaw in the party.
Now if Americans saw the Dems be decisive here, get Biden out, get Kamala in with a VP pick fast and out there campaigning as two non-senile people, what Americans will see is a decisive and smart party not scared to make the somewhat scary moves when the evidence is overwhelming, rather than deny reality to every American who is not a hardcore Dem. It will show strength and an ability to be dynamic.
But it has to happen very soon, and it has to be as smooth as can be. The Dems will prove that yes indeed, they are a party that can stop Trump. Cause right now, they look pathetic, and they were warned about this very screw up for years!