There's no "higher power" within the Democratic party that can step in and just decide to ignore the results of the actual primaries. That's not how the system works any more. The primary elections matter, and the results of the primaries are what will determine the nominee - not the convention. Even if you wish it were otherwise, if only for the entertainment value.

We're going to have to agree to disagree here.
You're underestimating the power of the if Trump wins the BAD ORANGE DEMOCRACY DESTROYING HITLERMAO DICTATOR TAKES OVERANDTHECOUNTRYASWEKNOWITISOVER effect will have on democrat voters. You can't sell the vision that the country is literally over if Trump wins and then roll over at your convention if your primary candidate isn't good to go.

The democrats have sold that vision for 4 years now; they've painted themselves into this very corner.

Let's put it this way. Consider this board and the lefty posters on it.

Let's say that every single one of them votes for Biden in their respective caucus/primary *but* it becomes clear next summer that Biden is physically unable to run for President.

Do you think a single one of these people would hesitate to say, "Please run Gavin Newsom" in that case, if it was obvious that Trump was going to otherwise win?