Which is precisely what will happen. Cruz and Kasich will be responsible for handing the nomination to one of the GOPe's picks, who like in '08 and '12, will lose to the Democrat1. Then the GOPe - who hates Cruz, will seize the opportunity to stab him in the back, blaming him for the Republicans' loss (it's all Kabuki Theater). Win/Win for the GOPe, Lose/Lose for Cruz.
Kasich, who may not be as brilliant as Cruz, is much more savvy in the way of the GOP machinations (don't discount longevity in the GOP). I'm sure he's negotiated a nice cushy post-election position for himself.
Who do you guys think votes on the rules?