I personally doubt that ebooks have 'lost their shine', I think this is more a matter of a journalist not being able to read into the numbers.
I haven't bought the report, but what little I know about the book market, I know that in 2016, adult colouring books became a BIG thing, really big! Are you going to buy those for kindle? No, so more money is spent on physical books and less on e-books.
If you're an ebook reader, you may also have noticed that Amazon has significantly raised prices on e-books in 2016. 25-50% on average it seems to me, and I often now see ebooks that cost the same as physical books. Now, I'm not going to buy a physical book because my ebook price has increased, but I do buy slightly fewer ebooks now.
Physical books have their place, but I don't see ebooks in serious decline in the near future.