I picked "other," since what comes in the future is usually something totally unexpected. Probably, some other culture will emerge to overshadow the US, although we likely won't even realize it--any more than the Greeks and Romans realized their own cultures were in decline until it was long gone.
There is an evolutionary process at work. Those societies that flourish are the ones that allow the greatest freedom to produce. The socialists may not like it, but government economic controls thwart economic growth. Learn it, or lose out.