At this point, it is impossible for Cruz to win. He has 465 delegates. He needs 1237. There are 800 delegates left. That means he needs 772 of those remaining delegates. He can afford to lose only 28 more delegates out of the entire remaining primary season.
Even if Trump has a heart attack and dies, Kasich is still there, and the bulk of the remaining states are northeast and pacific coast.
Cruz cannot win enough delegates to take the nomination on the first ballot. Both he and Kasich remain in the race purely to stop Trump from winning.
One analyst on CNN said last night that if Cruz OR Trump do not win on the first ballot, that neither of them will walk out of the convention with the nomination. He claimed to have sources.
Upcoming primaries are not the only way a candidate can add to his vote totals. Uncommitted and released delegates get to vote too.
Every card carrying member of the eneMedia has "sources".
Cruz is going to be hundreds short of 1237 no matter what, so there's little chance he can assemble a first-ballot coalition, especially since he's been so demonstrably unsuccessful in working with his Senate colleagues to date.
I still think Trump will arrive in Cleveland with the required majority to avoid any drama, but something to think about. Cruz is letting himself be used by the RNC under the mistaken assumption that they'll reward him when in fact he'll be tossed aside as easily as used dishwater by the GOPe. All he's really doing at this point is cutting himself out of any consideration for a role in the incoming Trump administration.
The delegates don’t actually cast their votes until the convention. In many cases they can cast their vote however they wish and not according to the primary vote tally.