Right. Absolutely. But I assume you wouldn't recommend running a dollar longneck as a regular menu item. No matter how much business you drive into your place, if the numbers at the end of the month, or quarter, or year, are off, they're off. Sure. Suppose I increase sales of tallboys by, let's say, 300 bottles a night. I'm not making anything like as much as I should on the beer, and I'm drawing drinkers away from PROFITABLE items, like draft beer.
No one with half a brain would say that it's simple. Even I wouldn't, and I don't even have half a brain left. And I'd be the very very last one to stick up for the pencil pushers. But I'm here to tell you that if, at the end of the day, you've got a bar or restaurant with a 30% beverage cost, you won't have to do those calculations much longer.
Sure, there are variable, as I tried to point out. There's a labor/foodcost balance that can go either way without affecting profitability. And there are intangibles. And you can do wonders by getting folks to order your signature appetizer which adds six bucks to every check at a 10% food cost (anyone want a Bloomin' Onion?). But in the long run, you can't beat the numbers.
Your food cost and bev cost are, substantially, the ONLY variable costs in the joint. When they go up, profit goes down. And increasing the amount of unprofitable business just opens your veins a little faster.