...IMHO enough of the cruz voters would go for Trump to give him the number of required delegates if Cruz gets out. It is also possible that Cruz might be happy to be VP and make a deal with Trump.
...IMHO a lot of the Trump support is based on anti establishment feelings by the base. Cruz has been semi campaigning as a non establishment candidate also.

Liberals are like a "Slinky". Totally useless, but somehow ya can't help but smile when you see one tumble down a flight of stairs!