Perhaps that's true for your definition of "better off", which is perfectly fine, but it isn't universal. Even though I don't do drugs, I don't think it should be anyone's business to police what other people do with their minds and their bodies on their own time, as long as they don't pose a threat to anyone else.
One, those substances are fine for a lot of people.
Two, some of those substances are fine for most anybody. I've never even heard of a deadly marijuana overdose, and the evidence shows no increase in mortality for marijuana users.
Three, we already tried alcohol prohibition, and we are currently trying drug prohibition. It does not solve he problem you care about, while creating other large problems.
So really, you sound like somebody who has a personal hobbyhorse and uses pretty much anything (like say, losing stars on GitHub or mentioning a book on airplane safety investigations) to argue for it. And that sort of motivated reasoning around argument for societal change strikes me as way more dangerous than somebody eating a THC edible.
Perhaps if we think more like adults instead of infants we can try to understand complex issues better instead of reinforcing black and white stereotypes of the world or rehashing whatever our favourite source of ignorance tells us.
It may be an even worse drug. People on drugs mostly have some awareness that their ideas aren't very good. But for those drunk on power, the fact that their same great idea has already been tried and led to total disaster is no cause for concern at all. You see, they're obviously smarter and better than the last batch of power-addicts who tried that, so they'll do it right this time. Heaven help us if we ever discovered a chemical intoxicant that was capable of making people that deluded.
If no one in the world drank, smoked pot, or did drugs, how much better off would we all be? 100,000 deaths come from alcohol use every year in the United States alone[1]. That doesn't even account for countless cases of abuse, broken families, crime, and other negative effects of alcohol and drugs.
So many people say "oh well it's fine if I do it, I'm responsible" but then at some point someone isn't fine and isn't as responsible as they think they are.
[1] https://www.cdc.gov/alcohol/features/excessive-alcohol-death....