Romney WON the primary!
To win you need a ground game, you need people to nudge others to caucus or to vote for you with a get the vote out effort, you need internal polling and you need to ground and pound the early primary counties in states not hold 1 or 2 rallies in stadiums. Trump has no ground game, no get out the vote effort and he doesn't even have all the precinct captains in Iowa get to caucus for him. In this part of the primary Donald can have those crowds if he can't mobilize them then he's this cycles Howard Dean then so be it.
You got the news late. Santorum actually won Iowa by 34 votes. Yep. Count ‘em. 34 votes.