Except if your name is Nixon, or Reagan, or Bush.
Except none of those guys really embarrassed themselves.
Nixon damned well near won in 1960.
Reagan got very close to unseating a sitting president in 1976.
Bush did well enough in 1980 that Reagan felt obligated to put him on the ticket.
Perry, well, let me name three reasons why he isn't in that class. Bad preparation, eliminated before the third primary... and I forget the third one.
First impression. Second chance.
Goalposts, MOVE!
No, but I think you are a tad dense.
The first impression Nixon made was a competent Vice President who came within a hair of winning the presidency. The impression he made was about half the country kind of liked him. One could even argue Nixon invented the modern Vice-Presidency. (Quick, without checking Wiki, who was VP before Nixon!)
Reagan made a pretty good first impression in 1976. He got in late, challenged Ford (a sitting president) pretty effectively, had a strong enough showing at the convention to where deals had to be made to get a unified front behind Ford, and he was talked about as the next Nominee hours after Ford conceded.
Bush-41. Already had a really good record as Congressman, Chairman of the GOP, Envoy to China and Director of the CIA. Made a good showing against Reagan and was put on the ticket because Reagan's precieved lack of depth on foriegn Policy. So he made a REALLY good first impression.
And then you have Rick Perry. Got in the race late, because the GOP Rank and File didn't like Romney. Went into debates unprepared. Had a really strange appearance at a fundraiser where he was talking about maple syrup and acting like he was stoned. Did some Class Warfare stuff that kind of scared the GOP Establishment. Then he couldn't name which three departments he would eliminate.
In short. He didn't make a good first impression. He made a BAD first impression.
Now, yeah, it's feasible he could take the time to rehabilitate his image. Make a bunch of policy speeches and appearances where he doesn't come off as a slightly more retarded version of George Dubya...
But frankly, while those other three guys had crediblity and momentum from their first runs...
Perry really damaged his brand.
Now, if you are going to continue to be dense, I'm really not sure what else I can do for you.