All the discussion about Cruz's chances compared to Rubio is pointless. The establishment is never going to back Cruz to prevent Trump no matter who would be willing to drop out.
An extremist tea party true believer is just as terrible to them as Trump is. While a lot has been made of Rubio's tea party beliefs, he has demonstrated to be careerist and unprincipled enough to sing the establishment's tune if that is what's needed. So the non-Trump part of the GOP rallying behind Rubio is at least a possibility, with Cruz it's never going to happen.
An extremist tea party true believer is just as terrible to them as Trump is. While a lot has been made of Rubio's tea party beliefs, he has demonstrated to be careerist and unprincipled enough to sing the establishment's tune if that is what's needed. So the non-Trump part of the GOP rallying behind Rubio is at least a possibility, with Cruz it's never going to happen.