It's possible that America may never be "great" again, even though it is still a very powerful country. China has a larger land area, a far larger population, and the largest economy in the world. It eclipses the USA by a long shot. India is rapidly rising. North America has debt levels far beyond its annual gross product and no means to increase that product because its resources are finite. When you cannot pay back your debts, the economy balances on a knife edge. Even the interest on the interest seems to be beyond the country's means to repay. North America is heading for some terrible shocks.
You have bad information. The US economy is still the largest in the world. China is a somewhat distant #2. India's a very distant 7th.
I agree that US debt is way out of control but that just screws the middle class taxpayers for the moment. (North America also includes Canada and Mexico, by the way . . . ) Just wait until the USA can't afford to service all that debt when interest rates rise. The inflation will take off for the moon to reduce the value of all those dollars owed.
And we have no idea as to what China's debt levels really are. The "Party" keeps that information tightly under wraps.
Benedict Arnold 