Amazon's main strategy is to broker transactions between its users and the vendors that supply those users. Amazon is aiming to be everyone's primary retail store for everything.

Facebook's strategy is to own everyone's on-line "sharing". Google's strategy is to own everyone's "search" (broadly defined). Amazon wants to own everyone's retail experiences.

Amazon would love it if slick devices were cheap enough to just give away -- they'd know instantly how to make huge money off that. Google and Facebook? Not so much.