Tell me more

I'm always willing to learn. So tell me why someone would use less and avoid overdosing if the substance is legal, readily available and most likely cheaper?

Most people are neither abusers nor addicts. If you read the studies, limited as they are, a pattern that repeats itself is a short-term spike in use, then a drop. In country after country where decriminalization or legalization has been instituted for at least some substances. And all the associated social costs also decline while worker productivity and economic output increase. It's a no-brainer obviously except for the folks who think they are Puritans entitled to dictate morality to others, exemplified below by Dave's comment. Dave only does booze, tobacco and pharmaceuticals, though I suspect he likes sugar, too, one of the most dangerous drugs of all.

Why would anyone use more of a substance they already have access to just because it's legal or decriminalized? I don't see the connection. When I drink illegal booze I drink the same amount of alcohol as when I drink legal booze. I still have to live a functional life, do my work and pay my bills. Nothing changes.