I think its obvious Trump didn't like this healthcare bill and was probably glad it didn't go through. Knowing the type of guy Trump is, its way out of character how easily he gave up on this. When his first immigration ban was struck down he lashed out and immediately wrote a new one. Compare that to the AHCA where he was quick to pull it and didn't seem to want to put up much of a fight.
I think the more likely motivation is that Trump simply didn't want to work on healthcare. His repeated bashing of Obamacare aside, more interested in stuff like tax reform than healthcare, the former of which he couldn't tackle until the latter was dealt with. So he threw his full support behind Ryan's health plan, despite how many Americans it would negatively impact, because coming up with a better one would take too much time; similarly, he forced a vote on it because he simply wanted it done with, one way or another.
Basically, his every action seems to be that of a man just trying to get it out-of-the-way so he can do the stuff he wants to. I doubt he really gave a shit about it either way; I certainly doubt he was be against it for the same reasons many others were, such as the Americans who would have lost coverage or seen premium spikes. If that was the case, he would have pretty vocally come out against the plan. Not like the guy is a opposed to going against his own party after all.
Basically, if it passed, great, it's out-of-the-way and that's all he cares about. If it didn't, OK, he'll blame everybody else and insist that the bill's failure is a huge tragedy; it's still out-of-the-way, and that's all he cares about. .