Trump seems to crave publicity.
He is a speculator and not a very good one, as several of his investments have declared bankruptcy.
He would be a horrible president, but he has never run for anything before and not even the oligarchs of the GOP would give him the nomination. Of course, he would have to divulge a lot about his finances, so he will never actually run.
He claimed that people would be surprised about what his private investigators were turning up in Hawaii, but he never said a word more about it.