In any case, two things:
1.) Not how anything works. The President's party owns failures like this, fair or otherwise. Trying to shift it onto the other guys didn't work for Carter, won't work for Trump.
2.) Blame Democrats for what? Keeping people's healthcare in tact? Sounds pretty great to me! Putting this on the Democrats is so easy when they can spin it right back in their faces like that. Especially when it doesn't make sense to begin with since Republicans have the majorities, bungled it anyway, and them not getting blamed for such a failure goes against all manner of norms and is based on fuck all other than "Trump is different! He just is!"
Of course, the true diehards are going to believe him, but that was always going to be the case no matter what. Nobody else will be fooled, and to say otherwise is based on absolutely nothing and decades of evidence to the contrary and just a pure instance that Trump is different.