New England candidates almost always win New Hampshire in a walk and Romney couldn't break 50%. Worse, this isn't like 2008 where the states were winner-take-all for the Republicans. Romney will end up with, probably, slightly more than a third of the delegates from New Hampshire. The Iowa totals are really up in the air because of the way they're assigned at party conventions and Paul might have actually won the majority of delegates in Iowa because of his organization.
To put it bluntly, Mitt Romney can't get anywhere near close to half of the delegates from any state. Right now, Romney is pulling 31% in South Carolina and 32% in Florida. It's too early for polls in the later, most populous states like California, New York, and Texas so we can't call those, but Romney desperately needs a majority in each of those three to start chalking up delegates. Especially if Perry survives until the Texas Primary.
Worse, these votes so far are keeping challengers in the race instead of winnowing them out. Ron Paul is not going to drop out now, and unless he tanks completely in South Carolina, Nevada, and Florida he won't get out any time soon. Santorum will probably get a boost from South Carolina as will Gingrich. Huntsman may stay in for a couple more weeks. Every name on the ballot makes it that much harder for Mittens to start winning actual majorities.
This becomes a problem when the Republicans pack their bags for the trip to Mouseland and their Convention because the nomination ISN'T first-past-the-post; a candidate needs a majority of delegates to receive the nomination. What happens if Mitt keeps pulling 30-40% at best in state after state? He's not going to get to the 50%+1 of the delegates he needs, which means the Convention will probably be deadlocked on the first ballot.
And what happens on the second ballot? It's a whole new ballgame. The opposition forces will start cutting deals so the weaker candidates get out and endorse the stronger ones. Suddenly signs like "DRAFT PALIN," "DRAFT CHRISTIE," and "DRAFT DANIELS" might start appearing in which case all hell breaks loose. Mitt will have to fight tooth and nail to hold on to his delegates if a more charismatic candidate throws a hat in the ring because (much like John Adams in the musical "1776"

he is obnoxious and disliked.
Even if Romney makes it out of a brokered convention there will be no more bounce than your classic dead-cat bounce. He won't be able to use the convention to make his case to the American people and re-introduce himself. His campaign organization will look sloppy for allowing it all to come to that and the Process Stories will rule the day in the media about how fucked-up the Republican machine is at the moment. And if the "not Romney" forces manage to unite behind someone else on the third or fourth ballot he might not even leave the Convention as the nominee.
So, ironically, with two victories under his belt so far, Romney is even further away from the White House than he was before any votes were tallied.