"Legalize it so that it can be taxed and regulated" we were told. Well what if people do not want to pay more for those taxes and regulations in order to have their highs? Back to square one, I suppose.
The existence of some degree of black market does not indicate failure, especially where legal shops
are doing a large volume of business. That's absurd. You might as well advocate a return to prohibition because there is still some black market liquor out there. Moreover, it's the kind of logic that leads to absurd results if we take the principle - the failure of a law to completely stop a practice - and apply to it to any other law. For example, robbery. There are laws against robbery. Have they deterred some people who might otherwise rob? Maybe. But some people are never going to be deterred. Doesn't mean the law itself is somehow inherently flawed.
But as for pot, there is no reason to think a black market will completely vanish when it is legal in only a small minority of states. National legalization would seriously shrink the black market. I doubt you could ever get rid of it at this point, just like there is still
some degree of black market in liquor or wine even (ie, counterfeits).
The fact of the matter is that in legalization states, more and more users turn to the legal shops. States are making revenue. The experiment is going just fine. In a legal shop you know exactly what strains you're getting. You know exactly how much you're getting. You generally also get a readout of how much THC, CBD and other cannaboids are in it. Because it's well-regulated, you can be assured the grower isn't using any pesticides or anything that might remain on the flower and harm you, etc. You can buy edibles you don't have the equipment at home to make (nor are sold on a black market). Etc. The fact that some people might still seek even cheaper stuff on the black market does not indicate some kind of failure.
But the "back to square one" position has a further and bigger flaw: it shouldn't be illegal, period. I should never have been illegal. It's the safest recreational drug, way more so than alcohol. And the bottom line is the only thing keeping it illegal did was create huge drug cartels.
So "oops, there's still some black market" is by no means "back to square one".
Well...
California seizes $30 million in black market cannabis from illegal pot shops - Los Angeles Times
So if the state doesn't get their cut of the proceeds then it goes after "illegal" distributors. The good news is that those raids and fines aren't a "war on drugs" because....well, because...
Hmm, maybe legalization hasn't really fixed anything. Maybe all it did was cut the state government in on the trade.
Um, what? This is not logically coherent.
1. What was "fixed" was the huge socio-economic damage resulting from putting people in jail for smoking pot.
2. Yeah, DUH it cut the state in. That was part of the selling point to politicians.
3. It's different in any state. For example, in MA an individual can grow 6 plants; 12 for a couple. As long as not in public view (borrowing from 4th Amd. definition) and in a locked enclosure. You can grow your own/and or go to shops. The more people do that, the less on the black market.
4. Produce anything for sale without a license if you need a license (or without following relevant regs) and it'll get seized. I'm not sure what you expected legalization to mean, but none of the serious suggestions were "let's just have a pot free for all with no regulation". The fact that someone still tries to occupy a black market is not some kind of flaw in legalization given what legalization was intended to fix: the complete idiocy of jailing people for something that is by leaps and bounds safer than booze.