That's dumb, Cruz's public support is extremely soft. He has numbers where only small portions of his support even, apparently, like him, and aside from stealing a few delegates here and there, has no hope of winning if Trump doesn't get the necessary 1235 delegates. No one will be rising up to save Ted Cruz in a convention. Cruz's surrogates in the media, like Ben Shapiro, will drop him in favor of a "fresh face" basically as soon as they are told to do so.
His delegate support isn’t nearly so soft.
Meanwhile, Trump supporters, many handpicked by the establishment, will bolt by the hundreds after round 1.
That’s the point. Hell, that’s the race.