Maybe not "give them access," but I think we tend to underestimate adolescents' abilities to select out of behavior. From personal experience: I was able to access alcohol at a pretty early age, and thus avoided a lot of the "typical" American young adult experience with it (not drinking until college, at which point you black out at your first party.)

Tobacco is a step further in terms of addictive potential, but I think the US could generally learn from Europe's approach to adolescent drinking.