The problem is that the Republican base -- about 40% of the voting population -- wants Obamacare repealed and probably not even replaced. The GOP has been promising that for seven years without really meaning it. Most of the GOP establishment love whatever government programs will enslave the people to the government even more, so they want something that looks pretty much like Obamacare, just maybe not ignoring quite as many of the economic realities that Obamacare ignored.

That will take negotiation because the Freedom Caucus (who actually listen to the GOP base) are going to resist universal insurance and the GOP business elite are going to resist repeal. The GOP has a whole has to come up with something that won't alienate the people who put them in office on the promise they didn't mean while not also pissing off the people who funded their campaigns.

The smart choice is to repeal it altogether and start fresh, but that isn't what's going to happen.