Trump iss an 80% favorite for Nevada, Cruz and Rubio...10% each. The train keeps chugging.
If Rubio was a great candidate, he'd be able to beat Trump now.
He hasn't.
Rubio has been battling it out with other establishment candidates. As the other establishment candidates drop out, most of their votes will go to Rubio.
Bush dropping out helps Rubio immensely. Had he stayed in the race into March, it probably would have damaged Rubio permanently. Now there will be pressure on Kasich to drop out as well. Kasich may stay in until Super Tuesday when a lot of midwest states are in play. But there will be a lot of pressure on him to exit.
Many candidates, particularly establishment candidates, helps Trump the most. That's why there will be pressure on Kasich to go. Most of the establishment votes won't go to Trump. He'll get some, but most will go elsewhere.
In a straight-up, head-to-head vote, Rubio will beat Trump (as would Cruz). But if all three are in the race, it would probably come down to the convention. Trump will have the most delegates. He probably won't have enough, though.
For Cruz, the calculation would be that if it comes down to a three-way fight, if he finishes above Rubio in delegates, he could win at the convention. But if he finishes third, he has no chance. So Cruz doesn't have to beat Trump, but he does have to beat Rubio. SC was bad for him. It's a conservative state and he was well-organized but still finished third. If he finishes third in most states on March 1 then March 15, what does he do after that? I have no idea, TBH. The most obvious thing is that he would drop out, but he might not.
Trump will win Nevada. He will probably win most of the states on March 1. But what matters are delegates. All the states on March 1 are proportional states. Two-thirds of the delegates will be wrapped up by Super Tuesday. If it's a three-way race past then, it's probably going to the convention.