I'll read your entire post in a second.I think you are kidding yourself both in regard to how Trump could be defeated in a primary as well as what that would mean as far as a repudiation of Trumpism. Primaries are won by courting a parties base, and the current base of the GOP has absolutely no interest in a 'RINO' moderate--there's a reason men like Jeff Flake and Bob Corker are calling it quits. The other thing that electing a Republican does is empower the same congressional **** show we've been enduring for the last decade. Handing more power to Mitch McConnell sounds ****ing great.
The primary difference between Trump and so called mainstream republicanism is his willingness to say the 'quiet' part loud. Make no mistake the GOP is the party of Fox News, and that isn't going to change any time soon, certainly not in the next two years. And as long as those nutjobs are creating policy positions for the GOP they are going to be a destructive force in America, regardless of whether Trump is in the White House.
I think the chances of Trump losing in the primary are 1,000,000,000:1