Remember that Biden's candidacy was dead in the water until the South Carolina primary, where he dominated the black vote at the very peak of pre-pandemic racial hysteria. I think at that point, the establishment said "All right, here's our guy who can win with The Blacks and isn't a bomb-throwing radical." Make him promise to put an appropriate token in the VP slot, and you've covered all your idpol bases while furthering establishment policy goals.
Petty concerns like "electability" never factored into it, since up until 3 days ago the elite consensus was that absolutely anyone would beat Trump in a landslide.
Petty concerns like "electability" never factored into it, since up until 3 days ago the elite consensus was that absolutely anyone would beat Trump in a landslide.