Since capitalism will rarely allow more than 20-30% 'success' that leaves a huge percentage of your population feeling inadequate.
Sometimes it feels the focus on individual brilliance without context of social value impoverishes rather than nourishes.
It can induce an adversorial state of hyper competition, in and out groups and a heightening state of frenzy to belong that leaves little room for niceties like empathy and community.
The folklore of America's success reinforces the mythology of individual brilliance, but rational heads need to question without taking away from individual brilliance in the past, now or the neccessity of it in the future, the benefits of the colononization of an entire continent.
The downside to this single minded focus is the simple fact that individuals are disempowered. They cannot effect any change. It takes real community and society to effect even the smallest change and that requires a functioning social setup with community, cooperation, empathy and mutual respect. Any communal action will require large numbers of americans to cooperate for instance protests or activism, at that point americans will discover their social structure does not allow for it and will not deliver. There is very little if any sense of community. It's been engineered out. It's unlikely individuals who have been devalued and left feeling worthless will make common cause in a hyper adversorial social structure.