Romney was the only one left standing, but he was also the chosen candidate by the opposition, AKA the mainstream media in concert with the GOPe—as they are now doing with KrispyKreme.
The press did not have to lift a glove against Romney in the primaries because Republicans do their own maiming so well and they wanted to save their best ammo for the main event.
With the exception of Perry, who graciously committed Hari Kari, Cain, Bachmand and Newt were viciously attacked by the press when they took the lead. (Santorum was never a front runner) The entire process was designed to mortally wound any conservative candidate. It was hardly a shock that the (GOPe) chosen one walks through unscathed.
Both Perry and Cain self destructed,
That left Santurum and Newt who were almost designed to lose.
Santurum left his Senate seat booted by PA voters, then went to FNC.
and Newt left his House Speaker job resigning it because of all kinds of personal and professional problems, then went to FNC. He has too many problems+past baggage to list in this comment.
That goes back to my point. Romney had no real opposition last year.