It's VERY rare that I'd disagree with revrobor, and he knows and understands theaters as well as anyone. But I do believe that theater pubs have their place and can be a very smart way to go.
There are several successful theater pubs where I live, and I have some random observations on them. First, a HUGE percentage of customers in these places buy concessions, and they spend more than I see folks spending at other theaters. (A - pizza, B - couples don't share a glass of beer the way they'll share a soft drink.) Second, I've never, ever seen anyone get drunk at one of these theaters (this is over the course of hundreds of visits). And third, unless a market is overserved with such businesses, a theater pub can be special because it offers an experience that the chains can't.
If there's one big reason for all of the above, I'd say it's that theater pubs I've known are not perceived as bars that happen to show movies. They're not even seen as theaters that happen to have bars. They're more like theaters that have little cafes.
Keep in mind, this is coming from someone who could have opened 10 bars or clubs in the time it's taking to open just one theater. One big reason I don't want to do the former is that I don't want to deal with drunk, unruly customers. But, in my observation and in all the asking around I've done, I've not seen a hint that beer and wine create problems in a movie theater. Very simply, the customers aren't going to these theaters to get drunk - and they're not ordering beer after beer. When I asked the owner of one of these places if offering beer had created problems, he shook his head and said "none." He went on to tell me how his audiences were always well-behaved because they were adults, not teenagers.
My feeling is that when theater pubs are done right, they become an affordable, easy night out for everyone from twentysomethings to young parents to folks who just want to avoid all the noise, expense and hassle of the multiplexes. If people want to go out and get drunk, a theater pub would be an absolutely awful place to do it.