> If Biden quits before the convention Bernie’s delegates get to make him the nominee. <
If Biden drops out, all of his delegates are released. They become free agents.
In that case there would be more free agents at the convention then there would be Bernie delegates. If those free agents banded together, they could easily outvote Bernie and nominate someone else.
Bernie hasn’t dropped out. He was very annoyed when New York cancelled their primary last week and gave the delegates to Biden. He protested strongly about it.
Does that sound to you like someone about to drop out?
And who do you think the Bernie Bros will vote for if Bernie is somehow screwed out of the nomination if Biden drops out?
In 2016, 12% of Bernie supporters voted for Trump. They ars not fond of Hilary at all.