> My guess is that Amazon took one look at the books and saw that they could easily lower prices without suffering much in the way of profit loss.
Well, I hope you're right, but I think you're wrong. Here's why:
Amazon wants to dominate the world of retail, and Whole Foods currently targets a specific and smaller demographic than "The World". Amazon needs to expand the demographic to reach everyone else. The way they do that is by removing most of the expensive things Whole Foods carries, and replacing them with cheap, less ethical alternatives.
This means we'll eventually lose a lot of the things Whole Foods carries. For a lot of vegan and ethical suppliers, Whole Foods is the vast majority of their sales, and they'll just be shut down.