Wow, lots of comments stating that it was common knowledge, but some fact doesn't become common knowledge simply because everyone knows it. Everyone should also know that everyone knows it and know that everyone knows that etc. which only becomes true after the article is published. The situation is materially different - this is illustrated e.g. by the famous 'island with a blue eyed population' puzzle: https://en.wikipedia.org/wiki/Common_knowledge_(logic)

In this case one of consequences could be that previously during negotiations with Amazon suppliers couldn't effectively use the fact that Amazon would scoop them (even if both parties knew that it was true), and now they can.