Not soon any ways
The United States is still the wealthiest, most powerful, and cultural dominant country on the face of the earth. Relative decline is just that--relative. There is no reason to believe the US will "fall" in the foreseeable future. Only in the mind of the deluded doomsdayer is this even remotely plausible.
You can refine anything in it's pure form to use for good or evil. This goes for everything, not just materials.
The country will always have agro, industry, and service economies. I doubt there will be a total 'collapse' but it would be naive to think there wont be some sort of reckoning with regard to the debt, immigration, and reckless way the country has been managed. I DO think America will look very different in 100 years. Black populations will be much smaller, Hispanic populations much larger-the majority. The more I think about things, the more radically different things have the potential of looking...100 years from now. i dont think we will ever 'fall'...but there will certainly be change.
"No religion is true, but some religion, any religion, is politically necessary. Law and morality are insufficient for the large majority of men. Obedience to the law and to the morals are insufficient for making men happy. […]Law and morality are therefore in need of being supplemented by divine rewards and punishments."
So I could see rural areas becoming self-sufficient and becoming large communities with self-governance. Big cities, however, will be just as you said. Riddled with hardship. I wouldn't want to be there at all. I don't mind living within a couple hours of a major metro area, but that is about as close as I want to get.
Libertarian and Atheist...wow I'm a hated man.