I believe that behind closed doors Republican Senators are relieved that McCain has given them political cover; they don't want to be the dog that caught the car. There is nothing to support in the Graham-Cassidy bill. Absolutely nobody having any connection to healthcare supports it. The only supporters of this bill are the extremely rich Republican political donors who would have received massive tax breaks. One estimate says that Trump's own tax savings might be tens of millions of dollars. Republican mega-donors threatened to cut off political donations to Republican Senators if this bill didn't pass, and those Senators were willing to take healthcare away from 32 million Americans in order to keep the cash flowing. I believe that at least some of those Republican Senators, knowing how fundamentally evil this bill is and how devastating its passage would be for their base, are relieved to see it die and be able to say to their donors, "Blame McCain; I did my best. Send more money."