What's not to like about the idea of the American Dream? It's simple, desirable, appeals to the best in people, and hits on the productivity that comes with competition. Unfortunately it drags along the notion that if someone is a failure they deserve to be it. But people seldom get what they deserve, they get what they can negotiate. And while there are always ground-up success stories these exist because they contrast with all those who don't. The limited social mobility is entrenched and because all those who don't succeed in the possibility that they could if only they applied themselves (hah!), are punished for failing to do so. And any ideal that punishes for what is a necessary outcome is a really shitty ideal to hold.
But as far as its memetic success, it's an idea that's able to get people to vote against their own interests for the potential of something better. And that's really impressive, if not somewhat disturbing.