The problem is I don't see the supporters of all the petty candidates polling with a few percent or less coalescing behind one of Biden's challengers. Going through the list it seems likely that the supporters of many of the candidates will default to Biden when their guy (or gal) drops out, with the exception that I would expect a lot of the Yang Gang people to switch to Mayor Pete.
edit: there was also a good piece in the Baffler recently making the case that Marianne Williamson for all her talk of the politics of love is really just a huckster repackaging standard conservative bootstrap-moralism as New Age wisdom.
Warren voters (assuming she doesn't make the final two) will prefer Bernie to Biden, obviously. I don't really see Biden winning the overall nomination, unless there is some massive rigging - he is just a terrible candidate and the less he speaks the less votes he loses. But in the primaries he can't avoid speaking, and that will be when the reality will come out.

