Ready for another essay?
I apologize for not giving you the proper credit for the offshoring/corporate profits discussion.
I think we have radically different ways of viewing the world, much like opposing religious beliefs. I'm a "gold atheist," I see no value in gold other than some minor industrial uses. I don't value gold per se, I value gold for what it can do. And it can't do much. You, or at least the "gold bugs," see gold as intrinsically valuable, because... well, just because.
I can't dissuade you from your "gold religion," and you won't convert me, so that's why we've hit an impasse.
As far as you finding my previous comment irrelevant to the US/gold standard discussion, let me try and connect the dots for you to show why the US literally could not afford to buy gold to maintain the gold standard.
Trade Deficit
Note the sharp deterioration in the US trade deficit starting in the 1960s.
Budget Deficit
Note the start of accelerating budget deficits starting around 1970 (thanks to LBJ's Great Society social spending programs, aggravating the drain of the Vietnam War):
So if I can recharacterize your summary:
You: Why did the US leave the gold standard?
Me: We couldn't afford it any longer.
You: But you still have such large reserves!
Me: Those reserves are irrelevant to our reserve currency status, so we don't need the gold standard. Why incur the costs of a gold standard if we don't need it?
You: Irrelevant to our discussion about why the US left the gold standard.
Me: ???
Value of Fiat Currency
One more point about the strength of a currency. The strength of a currency derives from a complex set of factors, including interest rates, projected GDP growth, attractiveness of other currencies, and on a generic and somewhat redundant level, raw demand for the currency (e.g. through the current account). This chart is old, but shows the story of the dollar post-Bretton Woods quite well:
It's easy enough to see what happened. Stagflation of the 1970s made the dollar weaken considerably, as the US economy was in a malaise. Paul Volcker's high interest rates broke the back of inflation in the 1980s, and also made the dollar very attractive to yield-seeking investors. Then as interest rates declined, so did interest in the dollar, until the productivity revolution and economic boom of the 1990s made the dollar attractive again. Then after the dot-com crash and the rise of the emerging markets, the dollar declined once more. Ironically, the chart was created just before the financial crisis, but if it extended a bit more, you would see the dollar strengthen again as the whole world was plunged into recession during the financial crisis.
None of this can be explained by gold holdings. Gold is simply irrelevant when it comes to the strength of a currency.
There are other reasons why the gold standard is terrible, like the fact that the modern, deep, liquid, sophisticated financial system we have today would be destroyed if we returned to the gold standard, but as I said before, I'm not the best person to detail these arguments, and my posts are long enough as it is without writing a full-blown essay about it.
Conclusion
Again, it's unclear to me why you believe my previous comment was irrelevant, but I must be missing a key piece of your argument. All I can see is that we don't use the gold standard, and the world works. No significant country (or any country?) uses the gold standard. The main proponent of a gold standard in the US, Ron Paul, has never adequately explained why the Long Depression and Great Depression are superior outcomes to the recessions we've had since the end of Bretton Woods. If you have a good explanation, or can point to a good modern-day example of the gold standard yielding superior outcomes, I would be happy to read it.
Finally, I want to address your final paragraph: it is not the Chinese government that is buying gold, but rather Chinese citizens. I can't explain that behavior with certainty, but I can speculate that it's because Chinese citizens don't trust their own currency, and since the capital account is closed in China, they can't accumulate foreign reserves privately. Instead, they accumulate the next best thing, gold. Trust is the cornerstone of value in the foreign exchange market: do you trust that a government will pay its stated interest rates, or will it default? Do you trust the country will grow fast enough to sustain its debt load, or will it default? Do you trust the country will have the foreign currency reserves to pay you (if the debt is denominated in foreign currency), or will it default?
Gold engenders a certain trust among a small, semi-religious group of believers. But most of the population is like me, "gold atheists," and don't trust the value of gold. That's why the gold standard will not return.