The federalist has a pretty good article making the case against The Donald. Jim Geraghty notes when you consider the full Republican base, he polls badly, and in a head-to-head matchup with Hillary, she creams him. So what is The Donald up to? If you want my opinion, he’s s stalking horse for the Clintons. If Trump manages to do decently enough, by saying outrageous things that channel the base’s anger, I’d bet money he’s going to Ross Perot whoever the eventual Republican nominee is. Even if he could only pull in 6% of the Republican vote, that’s probably enough to throw the election to Hillary.
If I were a big Republican donor, I’d be thinking about kicking some cash to Bernie Sanders’ campaign. If he manages to defeat Hillary in the primary, you won’t have to worry about narcissistic billionaires pulling a Perot, because the idea of a President Sanders will scare the crap out of them enough they won’t want to play games.