The book business is in the early stages of its third great disruption in the past quarter century. The first two both changed the shape of the industry and created winners and losers across the entire value chain: touching every step from how authors got money to how readers got books. Significant institutional players were lost in both prior disruptions, and all the ones who remained had to change their models and practices significantly.
The cause of the disruption on both prior occasions and now was the introduction of asymmetric competition. Before 1995, publishing and retailing were the province of entities that did it in a businesslike way, usually for profit but always within an organizational structure dedicated to their publishing or retailing activity.