Both the greatness and the problems with America are related to liberty, the idea that people control their own lives, and benefit from their own choices & actions. Capitalism is an almost perfect match for liberty-seekers, but it's still an imaginary construct with artificial rules that can be exploited. Specifically, Capitalism is subject to three main weaknesses: monopoly, barrier to entry & accelerating accumulation of wealth, all eventual certainties to crash the system unless there is intervention, which is government's responsibility. In the case of monopolies, we have anti-monopoly laws, but they are currently being underenforced: just look at your limited selection of broadband providers. In the case of barriers to entry, government regulatory agencies have been captured; the pharmaceutical industry is an example. And in the case of accelerated accumulation of wealth, well, that's obvious.

This isn't a new phenomenon, aristocracies have exploited the weaknesses of Capitalism throughout history, but you can't fool all of The People all of the time, and eventually The People will overreact with a draconian solution like socialism. During the last rise of the aristocracy in early 20th Century America, we had a strong socialist upswell & we're having it again. With the stagnation of opportunity, and the weaknesses of Capitalism mostly to blame, there's a whole generation that's giving up on liberty.