The fact that many people go from heavy drinking to moderate drinking indicates that it is amenable to change, at least for those people. And your three years suggests that you are amenable to change as well.
I agree that it is really worth removing value-laden words such as 'moral' from the drinking behavior. Driving under the influence is harmful to society. People do hurtful things when they are drunk. The substance abuse is behavior which, in and of itself, isn't moral or immoral.