I've been saying a couple of things all along here: repeal is far from certain, and somebody will take the blame if it doesn't happen. Most recently, though, I was assuming that blame would fall on Paul Ryan. When the Freedom Caucus, spurred on by Ted Cruz, forced Speaker Boehner to shut down the government in 2013 based on the false premise that they could force Obama to defund Obamacare, that led directly to Boehner's downfall. I was starting to suspect that Obamacare would claim the next Speaker's hide too.
Trump, though, must be the center of everything, and here is where we see a critical difference between how Trump is attempting to manage healthcare and how Obama did. Obama didn't actually do much until the end of the process. He made a few public statements at what he thought where critical junctures. What he did early in the process was move the bill to the center, alienating liberals by, for example, stating his willingness to abandon "the public option" (a government-run plan that would compete with private plans on the exchanges). Other than that, he waited until he needed to sway a few votes, most notably Dennis Kucinich's, which he got by offering the little twerp a ride on Air Force One. What Obama didn't do was negotiate the specifics of the bill.
That's what Trump is now trying to do. By doing that, Trump is taking on a more central role, arguably, than Ryan, and if this thing fails, that may take the heat off Ryan because it will be Trump-- the deal-maker-- who failed, not Ryan. Voters are inclined to place outsized importance on the presidency anyway since the president tends to be the most visible figure in the system even when the president isn't Trump. Add to that a president who wants to be the center, and who makes himself the central figure in the process, and Ryan may be spared the wrath of the Freedom Caucus and conservative activists because he can blame Trump for screwing this up.
If it doesn't happen. If it does happen, then it's kind of a money-where-your-mouth-is thing.