This does seem the most important conclusion. What's likely happening is Amazon is no longer showing themselves as the top seller in some cases. Consumers are

This does seem the most important conclusion. What's likely happening is Amazon is no longer showing themselves as the top seller in some cases. Consumers are still buying on Amazon, but from a different seller, who does not charge sales tax. What would be impressive is if Amazon made an (algorithmic) judgment call, and showed price-sensitive shoppers that would otherwise go elsewhere the cheaper seller, and shoppers that would tolerate the tax the (presumably higher profit) Amazon offering.