If Biden drops out, there are two options: (1) the incumbent Vice President, who is already on the ballot; (2) someone else.
(1) Has strong arguments for being the consensus candidate. Maybe they work and Dems rally.
(2) Does not. Not any of them. Guaranteed chaos, infighting, and bitterness.
If the Democrats do push Biden out, I predict there will be no consensus on a replacement candidate, leading to infighting and, ultimately, a realization that the Democrats have a stable full of flawed candidates that cannot gather national support, particularly in a short time window.
Everyone asking Biden to drop out wants JD Vance to be president. If Biden dies, cool. Kamala is president. If Biden is incapacitated, cool. We have an amendment for that and Kamala becomes president.