Some people still fail to realize that the GOP is badly split. There's the mainstream Republicans who continue to go along with the RNC's agenda, and then there's the protest vote made up of those who are having no more of the RNC's bullshit.
A big part of Trump's support comes from the protest vote. That's why the RNC's media machine can't shake it loose. The protest voters know the score and don't give a damn what the media says about a candidate who is obviously in the way of the RNC's plan.
The protest vote won't turn out for any of the other candidates. Essentially, they comprise a totally different ideology than that offered by the RNC.
On the other hand, Trump is acceptable to the mainstream Republican voters. If Trump is the nominee, the mainstream voters will turn out to vote for him in the general election.
If Trump isn't the GOP nominee, the protest voters will stay home.
Hence, it's Trump or another Democrat administration.
I think the above is a very good assessment.
