Ironically, I suspect that Trump has unwittingly proved that the GOP establishment strategy of not being overly ambitious in its agenda, in marshaling political power instead of getting in big fight with Obama over budgets, was the correct one.
Because I think what Trump has taught us is that there is no voter appetite for conservatism - thus if GOP had gone pellmell after Obama it would likely have gotten its clock cleaned. People are not in the mood for hard choices or balanced budgets, which is why Trump smartly never emphasizes that.
The big lie is that support for Obamacare is soft.
The GOP establishment figured that Obamacare, as bad as it was, was going to be permanent and looks like they were correct because even GOP primary voters didn't care enough about Obamacare to nominate someone with a discernible replacement plan.