The left has historically had good luck with blacks in its electorate and they went to great lengths to pander to them - only one thing to concentrate on.
Now, they have more fringe groups than they can count on both hands and feet, and they are by-and-large pretty far out there in ideology and their demands for their votes. Abortionists, BLM, Antifa, LGBTQIA/MIA, Muslims, Indians, new ‘migrant’ hispanics and third world blacks and probably a lot more than I’ve listed (Jews are a group they’ve had since inception, but I think that’s going away, too).
The old adage, “you can’t please everybody” is becoming more and more difficult for them, especially now that they have a demented old, addled and arrogant, lying cretin as President with a predilection for little children. To run, he’d have to get out there and speak to these groups cogently and sympathetically and all I can see is that he’d slip into something like, “get off my lawn” even if he were capable of really campaigning like a candidate vs a predetermined ‘selectee.’
Problem is, the groups they are promising this to hate each other even more than they love the thought of free money, so Democrats have to keep borrowing trillions to pay them off.