This beta is rather inactive. I think plenty of questions surrounding wine for example, would have been nice to have seen.
A broader topic may have invited more general interest and activity. But whether that would have been "better," I think is arguable, to say the least.
To even gauge "better," we have to recall, what was our goal?
The very proposal was a Q&A site for beer enthusiasts. A general Alcohol SE would have diluted that purpose. In addition, there is a culture around beer (as there is a culture around wine), but there is not, to my knowledge, a culture around alcohol. Though an Alcohol SE may have enjoyed more attention, it may not have produced as likeminded (at least likepreferenced) a community as a Beer SE.
Of course, this is all hypothetical—I don't know what would have happened if the original proposal was for Alcohol SE and beer were a popular subject therein. (But for some reason I suspect that an Alcohol SE proposal may not have even made it to beta. Beer interested me right off the bat—I had recently moved to San Diego where there was a huge beer culture. Alcohol would not have caught my attention, and even if it had, I probably would have been turned off by the thought of thousands of questions about "mixology.")
Maybe you're thinking along the lines that a more general site, while losing its power of specificity, would at least have had a greater shot at surviving the beta. But besides that a general site may not have gathered sufficient experts to even get started (experts gravitate toward niche sites), what's the point of survival if the site doesn't meet its intended goal?
Despite my (perhaps strongly) expressed views, I know there's no right answer. You're right that the site is pretty stagnant. But that may simply be its fate, and trying to salvage it any other way might simply make it something else entirely.