I think it is not so much dumb people as the selfish entitled people - the sort that are always looking disaprovingly at anybody who is getting anything they are not - and that is a huge demographic. The sort of people who get their nose out of joint at everything from someone taking more food at the buffet to people receiving welfare benefits (or even disability or workcover claims). It also flows over into everyone who thinks that it is unfair if anyone who is female/foreign/gay etc. has something they don't, and assume it is being unfairly taken away from them.

There is probably a correlation between that and dumb, but there is also a sizeable group who recognise that the Republican plan will increase inequality and believe they will come out on top in that situation. Trump and his cronies lining their own pockets will help a lot of other rich and unscrupulous people do the same.