If he wants to beat Trump Cruz has to win IA and NH. That would shuffle the deck. IA alone isn't enough, it will be dismissed as another Huckabee/Santorum fluke.
Down the road will the establishment vote go to Cruz if they honestly see him electable - Reagan cred yes but Reagan persona? Man that's a stretch.
The establishment is holding off until Jeb bombs in IA and NH. That will give them cover to rally to Rubio, their second choice. Cruz might get their votes and money if it's down to him or Trump, but I don't rule out the deal maker cutting one with the GOPe and locking things up by April.
And, like the leaders in Congress going to Nixon and informing him that there were the votes for impeachment, the PAC folks will go to Cruz and tell him he can't get elected - and anybody not enamored with Cruz will tell you that's true after viewing his smiling "I'm Ted Cruz and I approve this message."
Remember, the difference between truth and fiction is that fiction has to be believable. I see some mea culpa from Rubio and cover from Cruz. Rubio may even announce he would take Cruz as his VP - which Cruz would laugh off until the convention.
Things are so shaken up today you may see a threesome on stage where Trump accepts Secretary of State, Cruz accepts Attorney General and Rubio promises to adopt Trump's "bring the jobs back while actually building a wall" and promises to be a pure "social conservative" for Cruz.
Rubio is your donor class candidate that might win under some strained circumstances.