How can you compare this to Microsoft!!! It makes no sense -- none -- whatsoever.
Microsoft owns the copyrights to Windows and the related interconnected software stack to which there is no interoperable substitute software due to trade secrets, on the spot updates, and copyright restrictions on reverse engineering and on selling and distribution. And all nonMS PC apps require a functional Windows underneath. Where a pseudo competitor can arise (despite Windows today being much more extensive than DOS ever was), the hopefully small but many differences give network effect advantage to the incumbent. In brief, it is very difficult to create a PC platform that goes around Microsoft or create an app that sells widely that doesn't defer to Microsoft in various ways. In fact, without the Microsoft antitrust, it's almost certain software today would be very different. Microsoft would own most of it, and they would have broken the web (embraced, extended, extinguished).
Amazon, in very sharp contrast, most certainly does not own books and reading material. Exception exhibit number one, the Register. In fact, Amazon hardly owns copyright as a fraction of the total "consumed" by consumers and in any case would have to buy such rights at huge expense (and will never own near all of it). Additionally, Amazon does not come close to owning the distribution channel. Exhibit number one, that the Register didn't have to pay a dime or require any permission for their work to reach me. It's easy to sell off a website. And last I checked, stories didn't require compatibility with Amazon's framework [Note the contrast to software where it is easy to sell off any website, but the product must still play by Windows rules and compete against Microsoft competition.]