The problem is that Gingrich was already the insurgent, with huge momentum out of South Carolina, and then he had a good one-on-one matchup with Romney in Florida, and got crushed (so badly that even with Santorum’s entire vote count, he couldn’t have beaten Romney).
Then, he essentially skipped the next 5 contests, choosing to go for a “super tuesday” strategy. Maybe that will work, I certainly hope one of the two (Santorum/Gingrich) can get momentum back and win, but Gingrich has become an afterthought everywhere but in a few conservative circles, so he’s got a tough road to travel to get the general population to remember he’s around and move back to him.