OK I will give you my take on it.
The GOP establishment (GOPe) knows, understands and is convinced that Trump can not be bought. Trump does not need money from rich donors such as Robert Mercer. That fact threatens their empire of easy money making life of in DC.
The GOPe has realized that all of their favored candidates such Bush, Rubio, Kasich etc can not get 1237 delegates. The last hope to stop Trump in their minds is Cruz. So the GOPe is piling on to the Cruz hope.
The fact is Cruz needs 87% of remaining delegates to reach 1237. Mathematically possible, but in real world, impossible.
If Trump falls short of 1237, guess what is going to happen? The GOPe will toss Cruz out like a used toilet paper, and anoint one of heir chosen ones as nominee.
I think the GOPe screwed the pooch when they did not go all in for Cruz after that little meeting jeb hosted in Fl before the primary
No, someone came up with a clever little game to let Marco try to take Florida and Kasich to take Ohio, then turn to Cruz
Problem was Marco just divided the FL antiTrump vote with Ted, and Kasich became convinced ( or was convinced) that he was the party’s true Great White Hope, so now he’s just an embarrassing spoiler who is hurting Cruz, not Trump
Fail
I don’t disagree with a single thing in your post.
I have read that there would be three votes at the convention before the Pubs took charge and put up a candidate of their choice. I don’t think that will happen.
What a strange election cycle.