I buy used books if available on amazon.

Book market will become more niche with people shifting their time more to online media. 

 I’ve been known to buy a book after I read it, if I really love it and want it to be part of my collection. I’ll also buy books of the authors I know. My Dad has a friend who is a successful author now. From the beginning he would go buy his new book the first day it was available. Pretty sure if I publish a book my Dad would go buy a copy first day it was available. 

 i talked to a friend working for a publisher yesterday, she said that this article isn't 100% accurate as in the age group between 18-29 the book sales went up again in the last couple of years ... still it's a tough market, especially as huge companies like meta trying to enter the market, which will be the end of a lot of traditional publishers