Earlier quoted context omitted.
You're not making an argument, just stating a disagreement.
Do you have any doubt that, say, Coca Cola Company could push heroin more effectively than someone on a street corner, if it were legal to do so? Do you think heroin is more or less commonly used than tabacco or alcohol? We've already seen from the opioid epidemic that drug companies at least are both willing and able to push massive amounts of an opioid drug on patients if it is even slightly legal to do so. Why do…
Certainly not advocating doing anything the way the US does it, in almost any respect. But the pharma thing is fundamentally a different issue. The reason people so easily become addicted to painkillers is because they're initially given for pain by someone they trust, while unbeknownst to them they've actually been given too much, for too long. In other words this is an issue of doctors abusing their authority.
Why don't I think it would get worse? Because of cultural norms. Legalising heroin won't make it cool and socially acceptable to use. People don't actually derive their social values solely from what happens to be legal.
Let me ask you a question. Why isn't everyone an alcoholic or a smoker? Why do they become rarer(in the west) despite those drugs being legal?
(Hint: the reason is cultural).