I just read that 100 years ago there were something like 30 independent breweries in Brooklyn alone, and that people would
go to the butcher, the baker, the greengrocer and the brewer on their regular shopping trips.

Apparently the giant manufacturers pretty much took over after WWII, but now they are in a panic because of the rise of microbreweries in the U.S. and abroad, as well as the superior products that are imported. Supposedly thats why Coors-Molson is now looking to take over Miller. They have to be huge to remain competitive.