I disagree....if this continues to go like it is, there will be a large number of registered Dems simply switch over to the good guys. It's happening now, and the minority numbers are shifting Red as well.
There is always the possibility the '24 Dem nominee will come from the Governor ranks. Governors have the ability to campaign on there statewide success and not be as tainted with the DC stench. Maybe a Roy Cooper or Andy Beshear could find a lane and do well.