It is impossible to effectively regulate and tax something that literally grows like a weed. There will always be non-regulated channels.
The state tried to “legalize” it by regulating and taxing it. That is not legalizing it, that is co-opting it.
True legalization would be a total lifting of all penalties and regulations associated with the production and consumption of cannabis. I think this is a horrific idea, but truly you need to, as a society, either accept it, or not.
BTW, I do think there would still be room for DWI laws as related to any substance that messes you up, as well as employers being able to put non-use as a condition of employment.
“legalized” weed was always just another way for gubbernment to get into your wallet and take your $$. All the rest is just details.