I prefer craft beers for two reasons: 1) They taste better. Beers by the large corporations taste like piss. They're only purpose is to get drunk quickly. While some might claim that's a more "efficient" way of drinking, I have to disagree. Why not enjoy what you're drinking? Does that not increase the "efficiency" factor of it? Sure, craft beers cost more, but you're paying for what you get. Left Handed Milk Stout is delicious, as is Magic Hat #9. Good beer is something I'm willing to pay a little more for. 2) Buying craft beers is sticking it to the man, man. While small companies do have the opportunity to make something of themselves with how our economy is built, the large corporations stifle them. In buying craft beers, I like feeling that I'm pushing the little man along and leveling out the playing field.
In actuality often the "efficiency" of the beer can be increased by it's alcohol content. Local and craft beer makers will usually sell a beer with a higher alcohol content than beers that are mass produced. The craft beer I drink is often twice that of a normal beer (6.4% or greater), so it takes fewer drinks to reach the same level as a mass market beer.
I guess I was referring to the price of the beer over it's alcohol content, but you have a good point. Not too many people look at this small detail though and I believe that's a reason as to why people get the cheaper beers.
Then good for them, and I'll move on to the next small craft beer. Unless it was honestly that delicious that it's worth continuing to buy.