Of course not, because any scenario where Cruz beats Trump is on the second or third ballot at the convention where the winner of the popular vote (by a pretty substantial margin) is being robbed of the nomination. That's not the point. I'm not saying whether Cruz should or shouldn't. I'm saying Cruz is a spineless worm and will back Trump in the fall because that's just who he is.
He hitched his wagon to the Trump train when the campaign began and now he's flip flopped because he can't really do that when the field is narrowed.