the opium experience of china, first, was unique in many respects and was not repeated in any other country, and second is a great example of why governments should not be taxing, especially for general fund uses, any vice. Even the Maoists, the occupying Japanese, and the standing governments for over 100 years derived most of their funds from opium taxes. The Opium wars themselves were complex, and opium imports were not the only reason (note that by the time of the second war, or soon after, domestic production of opium in 19th century China dwarfed imports, Opium was a major economic engine of the country).
And of course, both Opium wars were fought, and lost, not because China was going broke from importing opium, but because the british desperately needed to export opium because they were going broke buying Chinese goods. By the second opium war, even with open opium trade, the British were importing 9x their exports to China (primarily Opium on a silver basis). China, contrary to the common story, was richer than sin and Opium was basically where they were spending all those riches they were sucking from the Brits. Losses were primarily due to the fact China had withered when it became insular after sending out its great fleet and seeing the rest of the world as backwards. It turns out you spend centuries not competing, you will collapse.
For a counter example of society functioning fine, there are estimates that 19th century America had as many opium addicts as we had Heroin addicts at the turn of the millennium. Think about that. Across a much much smaller population, there was heroin dependence on a large scale and yet not only did society function, but it thrived.
Opium usage through out the world points to a pretty self regulating outcome (as in, just like a virus can't kill all humans if it needs humans as a host, opium can't bring down all of society because addicts usually are not capable of influencing said society to make opium more available). And while you can point to the complexities of China as a great warning (as I said, I would not use taxes on these things to fund, say, schools, or medicare, or any such effort because of it) it is pretty unique in showing us a failing society because of widespread opium/heroin (and that assumes you believe Opium was the cause of their problems and not their complete lack of ability to compete with the west). Many of the things Europeans forced on China they forced on Japan as well, without opium as a trigger or a lever.
yes, I'm aware this was quite rambling. it is late, and as your response wasn't filled with righteous indignation about your moral superiority, I thought it would be interesting to reply. apologies for the horrible writing.