Like, Really Smart
Let’s start here: From everything I have ever read about the man, he is not particularly smart. This is sometimes hard for people to understand. They equate financial gain with intellectual gifts, but the two are hardly synonymous.
Being gifted at exploitation is not the same as intellectualism. It is a skill, but one separate from scholarship. Being able to see and exploit a need, void or insecurity in people can be an interesting, and even lucrative, endowment, but it is not enlightenment.
He is also not a reader. That is not to say that he can’t read, but rather that, given his druthers, he won’t.
A depressingly large percentage of people do in fact equate financial success with intelligence. These people can discount any number of stupid things Trump says and does by reminding everyone, "But he's rich!"