I don't know how old you were in the 80's, so perhaps you can't remember the prosperity of those times, but when Reagan took office, he had to clean up the small disaster that was the Carter Administration. And he did just that. He boosted the US morale far beyond its merits and he brought in a change for the better.
It's easy to make things look prosperous when you spend a lot of money and leave it to somebody else to pick up the tab. But that prosperity was illusory.
I was not a fan of Carter. But your view of him is highly distorted. The economic problems of his presidency were mainly due to the failed economic policies of the Nixon administration. Some of the improvements we saw in the 80s were a result of economic policies put into place by Carter and Paul Volker (appointed by Carter). And those Carter instituted policies would have been even more effective, were it not for huge budget deficit that Reagan ran up.
The military build up (for which some people say Reagan won the cold war) was also started by Carter.
Compassionate conservatism - bringing you a kinder, gentler torture chamber