In theory, I can kind of agree with you. But there are some very dangerous drugs which should remain illegal. Misuse of heroin even once can kill someone, for example.
In reality, we know this will never happen anyway. It would not be accepted socially, and would never garner enough political support for change. Pot, yes. Everything else, not a chance.
I agree, it's not going to happen but I wish it would.
Here in NY heroin is the #2 drug in high schools. It's cheap and kids can easily gain access to it. It appears they start with pot, progress to their parents pain killers and switch to heroin when their parents supply of pain killers dry up. Parents are all buying naloxone kits so they can save their kids when (not if) they overdose. My wife's friend has had to use the kit twice on her daughter. It's a horrible drug, ruins their lives but it's so addictive they can't stop after they try it.