Problem one, the Dems would betray their "Diversity over everything else" wing of the base.
Problem two, the window of opportunity to run a competitive race is quickly closing.
Problem three, Biden/Harris aren't going anywhere. If not Biden, then Harris will be the nominee.
If the Democrats were smart, they'd sideline these guys until 2028 when maybe some sanity has returned to the party and they can start fresh with a clean slate.
I think Beshear could be formidable. As to Shapiro, let’s just say lots of folks in the party aren’t that fond of members of the tribe