I think you're advocating for better mental health care and rehabilitation of addicts, which I agree with. However, the idea that addicts will destroy their lives regardless of whether they stop using, or are forced to stop using, their drug of choice is an extremely dangerous statement. Many addicts get better by changing their environment and quitting/going to rehab/etc.
Furthermore, heroin != vodka in terms of how addictive it is for the average user, and that's partly why only one of them is legal for recreational use.
Controversies about decriminalization aside, harm reduction exists as a studied component in addiction, public health, and psychology circles for a reason.
Alcohol destroys many, many more lives than heroin. Isn’t even close.
The important question isn't raw numbers, it's which destroys a greater percentage of lives out of those who consume it. If heroin were as widespread as alcohol, would it still be true that alcohol destroys more lives? We obviously can't know for sure without trying it, but preliminary results aren't promising.