They are slowly destroying themselves. Their cities are dying slowly but surly. It's only a matter of time before they are in some serious trouble.
I don't know where you're getting that. Every time I'm there, every major city has massive infrastructure construction going on. The rate of building is staggering. Their new roads, ultra-modern buildings and bridges, airports, etc make ours look like a joke.
If you're referring to pollution, then we agree. But if they're "dying slowly", they surely don't show it. I think the "slowly dying" part is a much better description of the United States.