That’s where Cruz plans on winning it...at the convention....not at the primaries. He and his advisors know a lot more of the delegates who will be voting. He doesn’t care if he gets to the magic number, he just needs to make sure Trump doesn’t.
He will likely lose in the general if this happens, but either he doesn’t realize this, or doesn’t care.
Nobody KNOWS who will win the general election: that’s why we hold them.
But Cruz has a much better chance of defeating the Democrat than Trump does.
Trump is a near guaranteed loser.