The GOP Establishment isn't deterred by flip-flops. Remember, the Establishment isn't ideologically driven. And, without an ideology, they're prepared to pander at will and will cheer on somebody who's good at it.
The Establishment's sole purpose is winning elections -- not so that they can do anything necessarily -- but so they will have charge of the committees and the budgets.
Their only interest is "running the deal"; it has nothing to do with ideology. Certainly, it has nothing to do with shrinking government (and, thus, the size of "the deal").
And, if winning takes "flip-flopping", so be it.
Even yet, you still gotta have a deal to run. Ideology or no ideology, if your puppet president won’t be a puppet faithfully moving when you pull the strings, but will welsh on you without warning, then that person is an illogical choice.