What major part of the republican base would Trump lose in a general election? Any republican that would stay home instead of voting for Trump or any one running as a republican would rather have Hillary Clinton as president. Can’t see that happening again.
Trump presents himself as a Banana Republic Juan Peron type “president”. Many conservatives cannot bring themselves to vote for the way Trump has defined himself. That includes both libertarians and evangelicals.
In balance, I talk frequently with many Black Dems who hang out at the same McDs I do in S and E Atlanta. They currently prefer Trump to Hilary. (Sanders is not on their radar.)