They will support him if they feel they have to in order to gain/retain power. If it looks like Hillary is a heavy favorite to win and the Republican "establishment" needs to throw the long ball to have a chance, Rand is setting himself up to be a viable alternative to fill that role.
I think you are wrong and these type even fought Reagan after he gained the nomination. They even tried to pull Gerald Ford out of retirement and some managed to run a third party candidate against him. This idea that they will some how come together to win is ridiculous. Look how they worked against Palin even after they got their man McCain. They pretend they aren’t ideologues but they are.