You're assuming primary voters care about Perry's problems. Most would be happy to attend a ranch with the "name" on it that Perry and his pals apparently don't find the least bit of a problem with. One would think this sort of humor was left behind decades ago but I guess not.
A good point was brought up about Romney, which is he hasn't moved any in polls despite Perry's struggles (in fact Cain was the beneficiary). I can't see the Bachman/Cain/etc vote going to him. It either gravitates back to Perry or some new savior like Christie. At this point in the race the party shouldn't still be casting around for a champion. All's not lost though, as the 5 people currently pledged to Huntsman will most likely go The Mittster's way.
Lastly, the talking heads (as usual) are waaayyy off on Romney being the strongest general election candidate. Forget about Romneycare. He is absolutely going to get flayed, seared and eaten alive over outsourcing. This is an issue that gets zero mention in a GOP primary as Republicans and their corporate backers look favorably upon outsourcing of American jobs. In the Rust Belt, its a far different story. When Romney ran vs Kennedy in '94, he was on his way to a far better showing than the usual fodder the state GOP tossed up. That was until Kennedy ran devastating ads featuring factory workers in Indiana who got thrown out of work because Romney's company bought them and sent their jobs to a cheaper overseas locale. He never recovered, and there's no answer for that. Simply put, what was the right thing to do for his job at the time (a venture capitalist) is completely incompatable with the job he seeks to attain now. His boneheaded statement that GM should have gone out of business ain't gonna help him much either in any area that they have a factory, places like, oh I don't know....Michigan, Ohio, etc - the very states he needs to win.
Bottom line is, while I don't mind the guy and he did an overall good job as Mass governor, he's a lot more vulnerable than people think and it has nothing to do with his healthcare law.