A cheap butter substitute terrified the dairy industry. As margarine became widely available commercially, the butter people did everything they could to stop it. They bought laws that taxed the stuff and enforced prominent labeling. In at least once place they required that margarine be placed apart from other groceries in a special closed off "Margarine Zone" of the market so that people would be humiliated to go in, revealing that they were cutting costs. And most of all, the color of margarine was regulated. It couldn't look like butter, so the yellow coloring was either totally absent or in a tiny dot in one corner of the bag of goo so that consumers had to knead the package for some time to get it all yellow before putting it in the fridge. To this day, margarine cannot be butter-colored in some places.
What was the result? Today margarine is everywhere that butter is sold. There is still very good money to be made from butter. There is also good money to be made selling margarine and similar substitutes. Everyone knows the difference. The butter industry was not destroyed; they just lost some market share. Had they invested in the margarine business at the beginning most of their loss would have been stopped.
The Internet is margarine to a long list of industries. The music industry stands to lose retail distribution, which is not only a great place to add marginal costs but the place where their unpleasant friends in organized crime collect their money. The movie industry likewise loses its chain to theatres and all the incidental revenue there. Anyone with a job that ends in "Agent" who doesn't work for the government is threatened.
The car dealers might be threatened too, but they've already got laws in every state in the U.S. restricting auto manufacturers to selling only through dealers; they're in a stronger position than the dairy farmers.
Wine distributors are trying to "margarine" wineries with specious laws as well, because they find themselves disintermediated.
It might be good for business people who feel threatened by these changes to spend an hour with Visser's book and take a lesson from margarine.