This metaphor, while it seems intended to challenge the OP, kinda reinforces it. Many countries and cultures give some limited access to alcohol at a younger age, and the result is generally that they end up having fewer instances of problematic binge drinking when they come of age. A little bit of exposure instead of complete abstention helps people learn to have a healthier relationship than letting them hit 21 and dropping them into the deep end unrestricted.

Teenagers learning how to have a couple of beers with a meal would be an improvement on them turning 18/20/21 and going and getting hammered on shots

It would be nice to ease people into alcohol over a greater amount of time, but with phones you're using them constantly and "avoid it" or "only have two" are not workable solutions like they are with alcohol.

In parts of europe you can legally drink wine and beer at the age of 14-16. In many parts of europe you start drinking alcohol at around 14-15 illegally but socially acceptable to some extent. I started at that age, which is the same age adolescents start going out and dating.