This statement was not originally a reference to beer, yet it's true. Selling is very easy if you buy the right items in the first place, but needless to say, it's impossible to do that and keep all your members happy. You could buy just one brand and you'd certainly sell a lot, since it would be the only beer available, but you'd probably have a lot of irate customers. The same thing would be true if you bought only local 'craft' beers, which most of your members have never heard of. So, some balance is called for here.
People are eager to try such a beer, but most are available only in selected geographic areas.
However, the craft beer interest across the country has inspired many of the national brewers to either create craft-type beers of their own, to purchase an interest in craft brewers, or to align themselves with these operations in order to diversify their product lines, and that is good for all of us. Most members will be forgiving if their favorite craft beer isn't on your list, but they'll be less happy if you don't carry the type of beer that they enjoy. A well-planned beer list will include a good selection of appropriate beer types, as well as a sound choice of specific brands. You need to have a good selection of them. Give some thought to flavored beers like the fruit-flavored lambics, especially when it's possible to serve them in a champagne flute with a fruit garnish.