I see you point and hoped Ted would, at some point throw, his weight behind Donald when it became apparent he would win the nomination. Unfortunately Ted seems to have gone the other way. He is going along with the anti Trump plan. Did they blackmail him? To me it looks like they promised to minimize the damage so long as he keep attacking Donald Trump.
I honestly think Cruz is angling for Attorney General or a nomination to SCOTUS. For Cruz, throwing his weight behind Trump in exchange for one of those spots does a couple of things. Most notably, it takes the nomination proces out of the hands of the GOP since together Cruz and Trump have 90% of the delegates.