Yeah I sometimes wonder about the current state of "black market weed" in SF
There are *so* many dispensaries here that I feel like most people 18+ won't wanna #### w/ dealers anymore and this will probably mostly be true in any other states where recreational weed is legal. But as you said, kids younger than 18 are always gonna smoke weed so there's definitely a market there. Wonder if kids ever "shoulder tap" (ask adults to buy for them) outside dispensaries like teens have always done outside liquor stores. Maybe, but I'd guess that they still mostly buy from dealers and those dealers will of course probably buy from the dispensaries and obviously mark up the prices to make a profit (and probably skimp too by taking some for themselves).
So for all intents and purposes, being a minor who smokes weed won't have changed much, except there will probably be few instances of them failing to cop (which definitely used to happen back in the day) simply because there's more readily available weed out there.
Also seems like growing has become far more popular. I mean, the folks who have always grown their own have more options to buy and sell but it also seems like folks who have never expressed interest in growing their own are getting into it.