The only way the Unaffordable Care Act passes is in a crisis. But it's chances if their party is in crisis mode are pretty good because none of them actually care about public policy. The Unaffordable Care Act could have any content whatsoever, and all of them will vote for it if a win is necessary in order to serve their power agenda.
If I were a conspiracy theorist, I would say that Trump doesn't really suffer from dementia with behavioral disturbance, as you might think from his 4AM rage tweets. That's just an act to create a crisis, make it look like their whole party is about to go down the tubes, and the only thing that will save the day is to give their side a big win -- NOW. Whatever public policy qualms any of them might have about the content will have to be put aside because of the crisis They have to pass something NOW because Trump is about to implode. His fall will consume everybody's attention for months, and in the aftermath their whole movement will be discredited and their side incapable passing any ACA replacement, ever.
Irony aside, this dynamic still works even if Trump isn't in on it, even if he really does have dementia with behavioral disturbance. In that case, he really could be about to blow a gasket and say or do something that even our political culture would require that Congress do something about. If that's about to happen, their Congressional leadership needs a win now if they are to have any chance of managing the blow-up in a way that does not discredit their side for a generation.
This would be the best-case scenario for the R Congressional leadership. They use the impending crisis of Trump’s dementia to herd their otherwise unwieldy Congresscritters into getting some major legislation through. This gives them enough credibility as leaders, habituates their members to following their leaders, that when the time comes to do something decisive to get rid of Trump, they will be followed, and pulling the trigger will work. If you shoot at the king, you better not miss, and uncertainty about their members following their lead is the biggest chance of missing if they try to remove Trump. But if they manage that, if they manage to rid the country of the Trump threat by leading the congressional Rs in decisive action, they will gain enormous credibility all around. They will have a pliant replacement for Trump in Pence, and the media and electorate will love them.
This rosy scenario is in stark contrast to what happens if the R Congressional leadership never takes charge. Their attempt at an ACA replacement belly flops because they let the process drag out. The plan is pulled apart during this lengthy process by competing ideologies within the party, and fears of voter retribution over unhappiness with the results of the replacement. Chances of passing anything dim as Trump’s rage tweets continue to be the only work product of a WH that is incapable and uninterested in getting legislation through. Trump’s poll numbers continue to drop, and theirs follow suit. The 2018 election starts to look like a disaster, and then their membership becomes completely unmanageable as they all go off in different directions seeking to save themselves and the party be damned. By the time the accumulated dementia, and the scandals caused by no one being in charge at the WH, reach the level at which something has to be done, the party splits over doing it. The leadership has to turn to Ds to provide most of the votes to oust Trump. it’s even conceivable that members from swing districts and states switch parties to put Ds in charge of both chambers, or they join the Ds in a coalition that takes over leadership. Their whole movement ends up despised by a clear majority of the electorate as weak, and their ideology suspect as crazy, half-way to total Trump crazy.
They’re skating on some pretty thin ice. Their only hope is to skate over it so fast that it doesn’t have time to break all the way through until they’re safely over it.