Its a cycle...
Democratic strongholds run their places into the ground... eventually it gets so bad they elect a Republican... they come in and clean it up... and once things are reasonably stable.. they go back to voting Democrats who run it back into the ground....
Can’t fix stupid.
It can be argued that stupid is not the problem.
The leftwing leaders that were allowed to live, came back and assumed minor positions of power from which they reinitiated their agenda.
Allowing the leadership to live is the problem