I think the breweries could back (buy) the right people to get this through.Unfortunately this (total repeal of a drinking age) will probably never happen because no one wants to have their name and political career tied to the mess that will happen during the adjustment of our society to this. The drinking age has led to ridiculous "coming of age" madness surrounding drinking. Instead of people growing up around alcohol and drinking in moderation we have a society that keeps it from everyone until right about the time they are leaving home and exerting their independence; what a horrible combination. Instead of drinking being no big deal it is tied in our society to exerting independence and coming of age. There will be a horrible adjustment for our society to finally get into a healthy relationship with alcohol.
If you leave it up to state you would surely have Colorado, Missouri, and Wisconsin changing the age to 16-18.