I have to disagree with you. If they wanted, Democrats could force out Feinstein and Biden. They choose not to. In Feinstein's case, Newsom has promised to appoint a Black woman to replace her if she retires and then they would be left with the dilemma of possibly primarying her in 2024.

I don't know what their excuse is with Biden. I'm guessing that as long as Harris remains on the ticket, they will allow him to run. This way she will "win" the election and replace Biden when he can no longer function. If they force Biden out, then Harris would have to run on her own and would lose miserably.