With US legal drinking age being 21, this eats into drinking at university/drinking after work, which is very much where bulk of socializing for young adults happens. Can't imagine it's not hugely affecting adulthood habits.
Eh, 21 limit was in place for all millennials and most of Gen X. And millennials drink like fish.
But lower teen drinking can lead to lower lifelong drinking. Habits formed during those years have inertia.