Why not just elect Hillary now? Why wait?
An independent run by either Trump or some GOP substitute (as Ben Sasse has threatened) only guarantees the Democrats of victory - and NO they are not the same. I, for one, would rather have Romney, Ryan, McLame, Grahmnesty, or almost any other RINO before Hillary. I really think that had Romney won, things would be much better than with Obama. Now, I am not advocating for any RINO - but I don't like Trump or Cruz, so I am going to have to hold my nose in November anyway.
That said, if Trump is going to play the game, he needs to know the rules. If I were going against him in a real estate deal and he used one of the many "tricks" that I am sure he has learned over the years to beat me, should I should "no fair" like a 12-year-old? The rules around selection of delegates have been around for years.
As I keep saying - if Trump can't make a deal to win the nomination (either by getting enough delegates or by working with some other person), then how is he going to make deals with Mexico, China, Japan, etc.? Is the Republican party tougher than Putin?
If somebody else other than Trump wins the nomination, most Trump supporters will either sit it out or will vote for the Dem.