Same with prostitution. If it’s illegal, that’s the reason human trafficking is so lucrative. People are going to pay for sex, very few sex workers do it willingly knowing it’s illegal. Not to mention having no safe legal recourse when assaulted or robbed.

There’s still a black market for cigarettes and marijuana, so there will be for other drugs.

Besides, you are advocating for regulating pharma by making it harder to access opioids, yet saying that all drugs should be legalized. If you mean by decriminalized, then yes they should be; in fact, they are up to 2.5g. if you mean as regulated (under prescription), well that makes sense, and it’s exactly how Schedule I works (and opioids are Schedule I, in the same category as heroin for example).

The infinite money loop is interesting, but let’s face it: it only makes sense for drugs where the tax income outweighs the cost of treating it’s harm. Sure, a frequent smoker may thousands in tax over their lifetime. But how much will their cancer treatment cost? And that of their family (who paid 0 cigarettes tax) from 2nd hand smoke? Or in the case of heavily regulated liquor sales, it is indeed a good way to make a profit, but it’s unclear if it’s an effective way to make alcohol consumption safe, considering the number of alcohol-related deaths are on the rise (3800 in 2021). Keep in mind those are during times people didn’t drive/go out that much.

So really, legalizing and taxing harmful drugs is not a silver bullet. It might help, or it might make things worse; no one knows until they try it, but it’s clear the latter is what makes everyone scared. Instead, people should implement methods that have proven to be effective, including more naloxone kits (e.g. make them free at hotspots, extremely cheap otherwise, and available as nasal spray in every pharmacy in Canada) and supervised drug consumption rooms.