All the stuff I got about the Republican primaries yesterday came from a conspiracy theory website, which believes that the primaries are fixed. That is, the Republican party is cheating; they purposely changed the rules in order to favor their particular candidate. Sort of like a reality TV show, that messes around with things so the producer's favorite can be the big winner.
I don't believe that's the case, but the way the Republican primaries are now...well, it very much favors the top 2-3 candidates. The other 12 candidates are pretty much out of luck; none of them have a realistic chance of winning the nomination. Even if a third of the candidates dropped out of the race tomorrow, their chances of winning are nil.
In general, having a lot of other candidates is good for the top three. The minor candidates end up splitting the vote amongst themselves, which makes them weaker and easier to beat. Let's say 30% of the voters are up for grabs. What's a bigger threat: 10 people who get 3% each, or 1 person who gets 30%? Clearly, the latter.
Conceivably, a candidate could get 10% of the vote in every state, then win the nomination, because everyone else split at under 5%.
The conspiracy theory people went into detail about Ohio and Florida, which were changed into "winner take all" states. Now it's a lot easier for one candidate to win those important states, provided that the vote splits up equally among their opponents. And wouldn't you know it? Ohio and Florida have vote-splitter candidates: Marco Rubio and John Kasich.
In the rest of the country, John Kasich usually gets 3% of the vote, tops. In Ohio? He gets 27%. He more or less splits the Ohio vote in half, making it much easier for one of the top three to win that battleground state. If you were a rich, evil genius like Lex Luthor, and you wanted to make sure one particular candidate won, you would secretly fund campaigns for hometown heroes in all the battleground states, just to split the vote. And you'd make sure those states were "winner take all" states, so your candidate could get the maximum benefits.