I've believed all along that trump entered the race with several goals. Neuter jeb, walker, rand and Rubio. Make the gop look dumb and bring chaos to the convention. Keep Hilary legal issues out of headlines. Brand Bernie a commie. Then quietly exit and give Hilary the nomination in the best position.
We will see if I'm right, if trump was only a troll plant to do these things. IF he self destructs over 2-3 states with unfavorable rules where he sunk zero resources, it'll seem like he was looking for an out. Nobody serious quits over something so trivial.