You can't conclude from one data point (China) what is the "natural progression" - and the available evidence from the USA when opiates were legal indicates the opposite.
You are going to dishonestly assert that "China" represents one data point? You are going to ignore the millions of people involved, and the nearly Century under which they suffered from drugs imported into their country, and call it "ONE DATA POINT" ?
And then you are going to use the pathetically small sample of drug users in the early history of the US as evidence that drugs were not a problem?
You are ignoring the hundreds of thousands of soldiers who suffered from the "Soldiers disease" after the civil war, and who were slowly building a demand for opium imports into the US before officials started recognizing this threat of drug addiction in the 1890s.
We were on the early phase of that drug addiction curve when officials took steps to ban them. *THAT* is why drugs didn't develop into the problem they became in China. China wasn't having a serious problem for the first few decades either, but by the time drug imports had been going on for 70 years, China was in a very bad condition. It was collapsing. This is why the much smaller Japan was able to invade and conquer it.