This is one of the most naive things I've seen in a while. Growing up we could always get marijuana (and a few other things). The people who sold it were already operation outside of the law, they were fine with selling to kids. Alcohol was much harder to get. We had to twist the arm of a friend older sibling or coworker to convince them to hook us up or steal from our parents. These people weren't depending on the income from booze sales to make their rent, it was a hassle for them where as the weed dealer was just doing what they were doing all the time. Legalize weed and even if the price comes down a bit there will still be less people working to actively get it into young peoples hands.
I smoke very infrequently and rarely buy my own, let alone stash it or keep it at home. One time though, somebody gave me a number and told me to call 'Smooth.' Smooth was the shit. There was a minimum buy-in of $40 and he would drive his clean, well-kept car to meet you anywhere and do the exchange. He was a regular guy, sharp-looking and clean-shaven, with a touch of that almost-too-much loving stoner friendliness. that was his full time job dude. did it like a pro, in and out no bullshit and a smile on his face. Local street price of $20 for a dub. To get drinks, people went in with fake IDs and had to add 5 to 10 bucks on the price of the bottle for the cashier to sell it, and it wasn't uncommon for them to get busted, or for cops to catch 'em in the act and shut down the store too. Dealing weed illegally is so much more simpler than dealing alcohol illegally; I don't know if legalizing and pricing correctly will change anything or hurt the streamlined and perfect business of people like Smooth.
I agree with everything you wrote, I had the same experience growing up. Weed was a phone call and short car ride away, whereas we had to camp out in front of a liquor store with one of our cute girl friends and have her ask lonely looking older guys to buy for us. One time she asked a "riders in recovery" guy to buy for us. That didn't go over too well.