It was only a matter of time before the political and economic reality set in for team Rick Perry. Their candidate, a religious nut and corporate hack was only going to appeal to the base of the party - not the crucial middle needed to win a general election.
Perry's campaigning was disastrous largely because he didn't know anything about policy and could not remember crucial facts (like the three branches of the federal government) during national debates. But is was also destined to fail because of the vastly wealthy Romney campaign that has poured millions of dollars into locking up the primary.
There's a possibility that Perry seriously thought he could become President, but I'm more inclined to believe he was doing the whole thing for self promotion. His verbal gaffes were so serious that it is hard to imagine he woke up every morning thinking 'I'm the man for the job'. Then again, self delusion is a remarkable motivator.
Regardless of the Perry Presidential saga, it was never really important anyway. Romney was always going to win, and the other candidates are simply jumping out of the way now.