My point is that it's manifestly stupid to suggest that China was poor as long as it did not have much gold or silver or whatever, especially when those actually flowed into China due to trade.
Quite.
1) China traded. Unlike Europe it might not have been a society basing itself on it, and where Confusianism didn't exactly condone merchants (low sort of people), but by golly did China trade.
We have tremendously interesting local Chinese archives of 16th and 17th c. Chinese customs officials were charting what were going in and out. (There is a by now classic customs official's PM on rhinoceros horn, aptly demonstrating the amazing range of Chinese expertise in differentiating between various African and Asian species. I.e. the Chinese were far from passive recipients of goods. They had significant expertise in differentiating between types of goods and quality where global trade was concerned.) And the volume of trade was huge.
2) China in the time period in question traded manufactured goods. That is a huge advantage. In modern terms it means a whopping trade surplus. They had the production capacity to provide for themselves, and sell a surplus to Europe, charging a mint for it too. One might as well slam the US in the 1950's as poor and backwards for being able to build whatever the hell it needed itself, and better than anyone else, selling their stuff to anyone, that is anyone who could afford it. That was China in the 16th and 17th cs.
3) So what we have is a situation where the Europeans, frantic to trade for Chinese goods, find that the only thing they have to offer for which there is actual demand in China is bullion. However, gold and silver is hard to find and even harder to get out of the ground. Not least if it's located on another continent, like South America.
But so desperate to trade are the Europeans, it doesn't matter. They mine, and conquer and build international trade networks like their life depended on it. And in some sense I guess it did.
This means as far as trade is concerned the Chinese are in such a position of strength, the Europeans were willing to jump through any amount of hoops, crisscrossing the world and making all the hard work, to scrape together enough precious metal to be allowed to exchange it for some of the Chinese produce.
4) That wasn't all bad for Europe of course. Mining is terribly complicated and expensive, but in itself tends to lead to break-throughs in chemical knowledge, better engineering (pumping technology being a major concern actually). And setting up a global system of trade was useful in the end. It's just that it was terribly expensive, risky, and in the end the human cost of it all was kind of huge. By the time a European trade got himself to China with enough Cadiz silver, he could rely on every ounce of it having cost a couple of Indians their lives in the mines at Potosi, etc. Still, the potential profits of this kind of trade is such that the Europeans are willing to run all the risks and invest all the capital. (And if necessary kill, maim and enslave as many people as it took in the process.)
5) And to spell it out: Profits were not made in China. If anything the Chinese profited hugely from the exchange of their goods for the gold and silver of the rest of the world, obligingly provided by the European traders.
The typical run for a European East Asia Company (I'm thinking of the Swedish one, as I happen to know it best), was to load up the ships with salable produce. Find a market for it, ideally directly in Cadiz, or at least make a trade for whatever would sell there. (As it happened Swedis tar, copper and ship timber sold quite well in Spain.)
At this point, if you're good and know your business, you could make a small profit on the exchange. It wasn't necessary though. The profit margin would be crap compared to what you were planning, and you might as well sell at a loss, considering the future deals in mind. The important part was to get as much silver (in Cadiz it was New World silver) as possible. Then you would be set to make the 30 month roundtrip to China (survival estimates being about 2 out of 3 to embark). Off you go to the mouth of the Pearl River.
When in China, you exchange your silver for as much of the local produce in high demand in Europe as possible: china, silk, laquerware etc. And it's the Chinese naming their price, in hard currency. At this point you, the European trader, is just buying at a direct loss. The profit is all Chinse. But just you wait...
Because, having made it back to Europe, you now arrive with a ship laden with the wealth of China, which the European markets just can't wait to gobble up. Profit margins from the sale of the cargo would typically be several hundred percent. Everyone gets rich. Well, everyone that survived. (Primarily that would be the company investors, who never had to go to China themselves, but anyway.)
The important bit to remember here, however, is that for the European trader the actual profitable bits of this complex exchange were ALL IN EUROPE. In China it was all Chinese profits, and with minimal risks and costs to the Chinese at that.
As a consequence, generations of (al)chemists in Europe kept beavering away at working out the process of making china, aka "the white gold". (Success in the 18th c.) There were any amount of attempts to acclimatise tea plants etc. in Europe, and every Tom, Dick and Harry going to China seems to have been tasked with working out how to make silk like the Chinese. (Plenty of industrial espionage going on directed at the Indian textile industry as well, not least by the French, since the Portugese had cornered the market on imported Indian dyed cotton fabrics.) Anything to be able to cut out the dangerous and expensive bits involved in trading with China. The situation held until the 19th c., when the British, having gained control of India, managed to hook China on Indian opium as a cheaper replacement for bullion.
And none of it was done because China was somehow poor. It was the opposite. Same with India, if perhaps to a lesser extent.
On top of that, this use of the gold and silver from the New World getting circulated to China still might have been the best use of it the Europeans found. Conventional wisdom would have it that having lots of gold and silver makes you rich. Perhaps, but only if you're the only one with it. If there is a sudden influx of lots of gold and silver, and everyone gets a piece of the action, the end result is inflation. Suddenly your gold and silver just doesn't buy as much as it used to. Very disconcerting, especially if you cannot work out why, and the reason the Emperor, with access to all the riches of the New World, ended up being constantly broke. A truly great power of the time, the Ottomans, also found themselves next to overwhelmed by it, and they weren't even in on the New World gambit.