Frankly I was being a bit cynical there, I grew up in a shit area with shit parents and just overall shitty shit shit sharoo. The long and short is that MY experience has been that these rules around age and buying stuff is:
Laws against buying things do nothing to stop kids from getting it
Conversely, the rules themselves make it edgy/cool to subvert
Kids I know could go to the store and just pay a bit extra to get this stuff, and it was the hip thing to do in my area. I'll admit to having tried some basic booze as a kid and I just didn't like it at all, it tasted gross, so I avoided it. I was never too worried about being cool so it didn't impact me in that "push through it and acquire the taste" kinda way.
Long story short I'm a bit biased on it.
It just took seeing some other folks talking about their opinions on it for me to remember my experience isn't the one experience. I feel that if it weren't so cool to break the rules, kids would be less interested in it. It's admittedly a relatively naive idea.
Removing the limits altogether are perhaps extreme; I think a good alt would be like I said - get some learning in school on the impact of these things. I've been out of school for a long time obviously, but at least when I was in school the lessons on drugs/alcohol were pretty poor IMO. Needs fewer scare tactics, and more real science. I don't HAVE kids so I have no clue what it's like today.