Not really. Trump was never a guarantee to win Iowa. Secondly, no person who's won Iowa has gone on to win the nomination in Republican Party politics. Notice the all of the most conservative candidates win in Iowa but they never do much more than that. The Republican Party is going to have to kill Cruz outright and not even be subtle about it.
Makes me wonder how the hell did he gain so much track all out of the sudden. How do people actually see some sort of hope and appeal in Cruz?
I wouldn't get near him with a ten foot pole and every time he speaks it's to pander his way through his own crap.
The worst part is he actually believes the **** he says.
He doesn't come off as the most likeable person. But he does have a record of standing up against a lot of policies that are unpopular with conservatives, even if it means going against other Republicans in Congress. The reason he and Trump are doing well is because conservatives feel betrayed by their elected officials in Congress. Trump is a complete outsider. Cruz is an insider, but is viewed as an outsider.