That's pretty much the way I feel. Trump had numbers in the 30s as little as a month ago. Now, he's down to 27% in the latest Quinnipiac.
As the Huckabee's and Santorums and others drop out, their support will NOT go to Trump or he would have it already. Rubio and Cruz will rise and, ultimately, it will be a face off between those two.
Don't know what the Trumpster-divers do. Maybe they stay home, which would be ironic given all their ranting about OTHERS staying home.
Nicely framed with pertinent turns of phrase, but that is slicing and dicing the whole story to make a picture that doesn't reflect the reality.
Trump has flew high before, then dropped some, then after Paris spiked again. Now he's dropped again after alot of negative press. But considering the amount of press and his own missteps, he's not dropped that far. That is a sign of strength, not weakness.
All he needs to do is bat the balloon in the air again to get his numbers up. Now as for the others, yes, as others drop out that support will consolidate to the top four. But if Trump, and he has hinted as such, would pick one of those: Cruz, Carson, or Rubio as his running mate, if he is still on top after the first few electoral contests, he would cinch the nomination hands down. You need to factor that move into the calculations.
So all in all, as good as your argument sounds, it's fairly weak. I see nothing yet where Trump is in danger by any other factor than himself. I predict better than 50/50 that it will stay that way. Cruz IMO is the only one with the outside shot if pulling ahead of him.