If this bill fails, it won't be because of one vote. Once it looks like it's sure to fail, more and more people will jump in the nos.
I think we're almost at that point. The momentum since yesterday has been towards the nos. As it stands, at the minimum, it doesn't look like a vote this week is happening (Collins + Heller + Johnson kills the bill). They get Johnson back just by waiting, but who else would they loose after a week long recess? Who knows at this point.
Of course, some kind of grand bargain could be found where medicaid gets 13 dollars in spare change added to it and everyone flocks to the bill, but it won't work like the house did, because rapid development of this bill isn't really possible with CBO estimates being needed at every step. So it might not be that easy, especially since every change just brings new numbers from the CBO into the spotlight.