It's important to recognize the completely out of proportion power that the far-left crazies will have in the primaries. They definitely don't represent the larger party and certainly not the independents. But they will have an outsized impact on the race because they're the agitated (and often professionally paid) squeaky wheels that will drive the primary process. I'm rooting for Bernie in this case. Because he will alienate the election-swaying independents and normal people.
Biden is just too blathery of an empty glad-handing suit, which of course makes him the perfect blank canvas on which uninformed Dems with an allergy to the far-left insanity will paint their perfect imagined candidate. He can't possibly rise to the level of their expectations, but his utility as a paint-by-numbers place holder for the TDS crowd could be very powerful. So let's all get behind the insane lefties! That's the path to Dem self destruction.
The scary thing is that this low percentage of their party has had success with boycotts and propaganda against conservatives and have alienated a lot of normal people. A lot of people are scared of challenging them because they could lose their job and have a massive smear campaign hit them. Biden would do the best in the general election but the primaries are going to be absurd. If I was Trump and Biden was nominated, I would constantly roll clips of him sniffing people and grabbing shoulders without commentary.