Times have changed from last July.
The difference now is that Trump CAN ACTUALLY WIN if he runs Third Party.
For the GOPe, their BEST course of action is to let Trump have the nomination and then find some disgruntled conservative to run Third Party.
If they do that, then Hillary wins, which to the GOPe is FAR BETTER than Trump becoming President on the Republican Ticket.
(i.e., we have one sick party)
My understanding is that it would be next to impossible to get on the ballot (at this point) in all 50 states.