The wealth was destroyed by the colonialism during the reign of the Manchus. The British exported opium to China, because there was a massive trade imbalance. This made the British the world's first drug traffickers. They went to war to force China to buy drugs. The profits from this drug trade helped finance the industrial revolution in Britain.

I agree that the world economy is not a zero sum game. That is the reason almost all countries have a positive GDP growth rate. That was not true in the 19th and 20th centuries, when colonized countries in Asia and Africa saw near zero GDP growth rates. After independence, most of them have had much higher growth rates. Countries in East Asia have had higher growth rates than any western country, because they were starting from a much lower base.