Our understandings are different, of course, and it's great to learn another perspective. I agree with much of what you say, I just think it weighs less heavily. But a few concrete points:
1) A minor point: China's massive and questionable investments in poor countries are not grants, but loans (at least, based on what I've read). They may be creating leverage over those countries via debt, similar to what the West had at least until massive debt forgiveness.
2) 25 years is a larger number than what I understand. Depending on how it's measured, China's economy already is ~75% of the U.S.'s size and growing much more quickly (though with many serious risks, as you point out). Also, they don't need complete parity, just the prospect of parity - that will be enough to intimidate neighbors. Finally, China currently can focus all their resources on one region; the U.S.'s are distributed globally - one reason Obama hoped to withdraw from some situations.
3) My understanding was that the Cold War 'containment' strategy was not based on the assumption that the USSR would reach parity, but that their Communist economic system was fatally flawed, would inevitably collapse, and all the West had to do was wait and keep the USSR contained. At the time, some did claim that the USSR would or even did catch up - IIRC (a hazy memory of the histories I read) Kissinger thought so and so did the CIA at some point(s). But mainly we tried to pressure them into failing; that's the popular wisdom for why Reagan engaged in an arms buildup and 'Star Wars' missile defense. Regardless, based on hazy memory of numbers from the 1970s that I saw a year ago, the USSR and Warsaw Pact grew to around 50% of NATOs economic strength.
> The United States Grand Strategy
From what I've read many times from foreign policy insiders, such a thing doesn't exist. The foreign policy institutions are so massive and complex, from Dept of State to Dept of Defense to the National Security Advisor and staff, to all the large subcomponents of each, to Congress, to all the career bureaucrats that outlast any President, that getting them all moving in the same direction is impossible. Also, those people are disappointingly and shockingly focused on the day-to-day; few have time for grand strategy. As one person observed,
If, as F. Scott Fitzgerald said, '[t]he test of a first-rate intelligence is the ability to hold two opposing ideas in mind at the same time and still retain the ability to function,' then the government is a genius.
I think you would enjoy the whole article:
http://foreignpolicy.com/2013/12/05/how-the-u-s-saw-syrias-w...