Problem is the Harry Potter books prove it wrong. Give someone something that catches their interest and they'll put in the time to read it.
Well, they bought them but did they read them?
I was a bookseller for a number of years and found out that when a book gets a lot of publicity or wins a prize, the title becomes a best-seller because people like to display it on their coffee-tables for the status. We employed someone who was an expert in getting people to do just that.
And the Harry Potter books ate now almost a generation old. The current generation knows Harry Potter from the films and the internet. As a bookseller, I can assure you that the Harry Potter phenomenon
was very much about genius-level marketing.
Also, look at the history of publishing. Books and Magazines boomed during the 40's and 50's and began to drop off after that. And now we have the era of eBooks and audio books.
Publishing is a dying industry.
Cheers!