We maybe overthinking this. Maybe Amazon just offered Waterstones a huge chunk of cash.
Waterstones can do a lot with that, from investing in its print book business to going into selling other lines of merchandise. It may just be that being a B&M store selling books alone can no longer a profitable business anymore. I don't like that conclusion at all, but it might just be realistic- use books as a loss leader to get customers into your store, then sell other higher margined stuff to those customers. Works for Amazon!