I have to take issue with the previous comment. The article is not discussing history, but rather the present trends of the American brewing industry. No one is arguing that low-alcohol beers have existed around the world for thousands of years, and even that they are historically the most common and popular beer, in Europe and the States. The article is suggesting that craft brewers in America, who have until recently focused on high-alcohol beers, are now turning to more moderate ones. They "design"/create these session beers to be consumed in greater quantities. So, the styles they emulate were not necessarily originally designed for this purpose, but that is one major reason they are being produced by craft brewers today.