What’s keeping him in the race is the delusional nature of his supporters. Think about all those points you wrote about what a horrible person he is. How many other candidates could survive even one of those controversies? He lives in an imaginary world of his own creation where whatever he says he believes to be true, and his cult like followers are so brainwashed that their perfectly smooth grey matter just soaks it up like a sponge. There’s precious little he could do or say at this point that would have his base leave him.