Most of Cruz's supporters appear to be people who are wishy washy, not really set on their candidate, while 60 or 70 percent of Trump's numbers are hard numbers. They won't change.
Cruz is intensely vulnerable, and if he won the primary (I doubt it, and I pray he won't), he won't survive the general. People who think Cruz has a chance are fooling themselves and just don't know their candidate's problems.
Bombast by bombast followers.