Well, during Reagan's presidency there was a lot of prosperity, but his reagonomics were a good part of the reason why the US went into recession afterwards. Ultra-liberalization of the economy just doesn't work, it brings short-term success but in the longer run it's a surefire recipe for economic crisis. It's like a paper castle: it's easy on your purse and you're living in a castle, but don't expect it to stand after a year or two.
Erh...fuck that analogy.
Basically, Reagan's economic views didn't work. That's why they were abandoned and why other Republican presidents stayed away from them. They still try to do things in that direction of course, but nothing that extreme...because it's probably suicide if you don't have Reagan's charisma/popularity. And eg Bush has neither atm.
But like Satis said, Reagan was/is very popular. I was just pointing out that, while being anything but a perfect president in terms of his deeds, he still easily kept office...so being a popular leader does have its merits over your deeds. I know quite a few politicians who are clearly incompetent all over the world and that could be replaced by ppl who're a 100x times as effective, but hey: being a 'leader' also involves being persuasive, loveable, firm. Whatever.