We don't have a good comparison right now... because allowing a good computation is considered a bad idea. Selling alcohol to people who obviously are going to drink and drive, people who are aggressive and drink is restricted in some places though.
The issue is that we expect most people to have a drink once in a whole and continue with their lives as usual. We can't realistically expect recreational heroin use with no long term issues.
We also can't realistically expect recreational alcohol use with no long-term issues either: alcohol kills about 100k people per year in the USA.
That's not a reason to ban it. The issues are caused by the user, to the user. If users are causing issues to others (violence, theft, drunk driving, et c), those are separate and already-illegal things that can and should be enforced. Arresting people for possession is basically like arresting them for pre-crime: "some other people who possessed similar things later went on to commit actual crimes, so you go to jail out of fear" is not a sane approach.
The possession and use of substances for the human body is plainly the wrong place to legislate: the war on drugs in the US has been a costly, racist, unmitigated disaster.
Probabilities matter. Cost-benefit matters. You can't just dismiss it with "well, some people don't commit crimes, therefore it's immoral to restrict freedoms." It's a gradient, and the people on the whole reserve the right to determine where the hard line is. This is one of the beautiful things about the fact the US has many states--each state gets to decide where they draw that hard line. If you don't like it you can find another state that draws the line elsewhere.
> It's a gradient, and the people on the whole reserve the right to determine where the hard line is.
Yeah, except when those hard lines intersect the bodies of others. Nobody has the right to tell me what can or can't go in my body: that's exclusively my decision.
For alcohol? I dare you to say that to the face of someone with alcohol addiction in family. It's a simplistic black and white view. We negotiated thresholds where alcohol is restricted (age, distribution, setting) while not banning it completely. Neither unrestricted access nor prohibition were the answer.
The answer hasn't been found, as there is still a gigantic unsolved societal disease in the USA regarding alcohol. Tobacco too.
Whatever you think is working (stopping sales at 2am or whatever) isn't. It's farce. Humans can't handle drugs, generally speaking, and permitting some whole ruining lives over others is the peak of ineffective ridiculousness.
The fact that humans can't generally handle drugs (alcohol included) is not a reason to waste time and money and imprison millions of people in a misguided attempt to address the problem. (Not that that was what the war on drugs was even for, mind you.)
The issue is that we expect most people to have a drink once in a whole and continue with their lives as usual. We can't realistically expect recreational heroin use with no long term issues.