This is a couple years old, but still well worth reading:
The study of business is afflicted by confusion between the results of a survey of what people think about the world and a survey of what the world is really like. At another recent meeting I heard a platform speaker announce that 40 per cent of books would be electronically published by 2020. A pesky academic asked exactly what this number meant and what evidence it was based on. The speaker assured the audience that the number had been obtained in a survey by eminent consultants of the opinions of the industry’s thought leaders.
I imagine most of the thought leaders had no more idea than anyone else what the question implied, or what the answer was, and did not devote more than the briefest consideration to their response, so I am not surprised that the median answer was close to a half. If you want to know the future of publishing, you will learn more by peering into a crystal ball. It will at least give you time to think.