First, a snapshot of the problem in the UK:
Tim Heffernan finds that the answer lies in the business of alcohol production:
Monopolistic enterprises control the flow of drink in England at every step—starting with the breweries and distilleries where it’s produced and down the channels through which it reaches consumers in pubs and supermarkets. These vertically integrated monopolies are very "efficient" in the economist’s sense, in that they do a very good job of minimizing the price and thereby maximizing the consumption of alcohol.
The United States, too, has seen vast consolidation of its alcohol industry, but as of yet, not the kind of complete vertical integration seen in the UK. One big reason is a little-known legacy of our experience with Prohibition.
From civics class, you may remember that the 21st Amendment to the Constitution formally ended Prohibition in 1933. But while the amendment made it once again legal to sell and produce alcohol, it also contained a measure designed to ensure that America would never again have the horrible drinking problem it had before, which led to the passage of Prohibition in the first place. Specifically, the 21st Amendment grants state and local governments express power to regulate liquor sales within their own borders. Thus, the existence of dry counties and blue laws; of states where liquor is only retailed in government-run stores, as in New Hampshire; and of states like Arkansas where you can buy booze in drive-through liquor marts. More significantly, state and local regulation also extends to the wholesale distribution of liquor, creating a further barrier to the kind of vertical monopolies that dominated the United States before Prohibition and are now wreaking havoc in Britain.
But those monopolies are making a comeback, namely in "two giant companies—Anheuser-Busch InBev and MillerCoors, which together control 80 percent of beer sales in the United States."
The Dish 