I’ve seen a bunch of articles about it this past week. With Biden there were a lot of prominent liberal voices calling for him to step down, not to mention the absolute lack of enthusiasm within the rank and file that was showing in polls - with Trump the party’s rank and file are on his side no matter what, so if a prominent conservative calls for him to step down they will be ostracized for it.
I’m a fan of the Capitalist Realist Shopping Cart Theory, myself.