Why does everyone now think Bush will win the nomination?

[Famous Mortimer]

Yes, I don't accept the premise of the OP, and those who think who think they know at this point who the probable nominee will be are just foolish and/or naive and/or uninformed in my opinion. Among other things, how these candidates perform under pressure will perhaps be the most important factor of all, and as to that we can merely just speculate, and like anyone, sometimes you just get unlucky and have a bad moment, and just screw up. So luck plays its part too.