I think it partly right.
I have some sympathy for those who felt disenfranchised to not bother turning up to vote. Suddenly, somebody pops up who has a version of charisma, who appears to have a folksy connection with them, who says what has not been dared said and who is not the "establishment" who have run things for ever.
Years pass. Support becomes entrenched and, more importantly, any voices of opposition are condemned as "anti American" "communist" and so on. Them and us.
There are, therefore, 3 binding connections (other than low intelligence) I see that still keep 1/3 of Americans supporting him.
1. To switch support means abandoning Trump. That accepts they were wrong to support him in the first place. That is a hard pill to swallow.
2. Comments criticizing him are "fake news" and they view only echo chamber sources of news (if at all).
3. His crown may have slipped, but look who will get in if we don't vote for him.