I own a bar so I figured I'd chime in with some personal observations of my customers:
The bulk of my customers drink 5-7 nights per week. We call them "regulars." They come every night when their shift ends, and most of them stay until close (although they are primarily service industry, so this is 5-7 hours per day). If they have a day off, they often show up earlier.
For these people, I think that one drink every half hour is an understatement. They're having a beer/cocktail every half hour or so, and mixing in shots, jello shots, etc. If they have limited time, they will up their rate of consumption. They're after a specific result.
I have no idea what percentage of the population they represent.
We have a lot of other customers who we see maybe once a week, every other week. Some folks come in to eat our food special and just have a couple beers and go. Stuff like that.
I think that you are probably in the latter group (or the non-drinking group) and so you don't see the former group. I very much agree that the heavy drinkers are not living normal lives; they ARE in fact permanently hungover (or should be--they learn to deal with it in various ways). It's a continuing problem with my own staff, actually.
Anyway, they're out there, they're holding jobs and making children, and they undeniably have a problem with alcohol. But again, I have no idea what percentage of the population they make up. Maybe I'm seeing the worst of the problems--but I don't actually believe that.