edit to add:

They should be forced to go down with the ship.

GOP knows this...so, they will let Trumpy lose election, cut their losses in effort to preserve the Teabaggers for another day... they will not offend them because of future elections and desire to retain power ....

...conceivably, patriotism might motivate the R's to do whatever it takes to move this ticking time bomb as far from the Oval Office as possible.

There would be more harm done by forcing Trump out than by taking their losses, trying to minimize the damage to other races and regrouping another day. This is why Cruz and Kasich were forced to drop out--they thought a contested convention would damage the brand. They didn't quite realize the consequences.

Their hope is that with him gone, fewer democrats and independents will vote, making it easier to save incumbents' jobs.