Doesn't mean nothing. It shows he can appeal to the GOP primary voters, how will he reach all the other demographics we need?
Just one example: Cruz takes a "no exceptions" stand on abortion. Wife, daughter, sister gets raped--Cruz says tough luck, lady. You should be forbidden by law from aborting the unwanted product of your rape.
Trump favors exceptions, and therefore Trump is more acceptable to the majority of women, on this issue. The "no exceptions" stand is approved by only 22% of those surveyed by Gallup.
Just one example. Go ahead, and dismiss this, but if Cruz were to be the candidate, bet that the dems would continually point out this example of his extreme positions.
So yes, something did happen that changed things. What changed was the elimination of the chance for an extreme social conservative.