Let's be honest here. Kindle family of devices is aimed at average consumers. It's sold at retail stores, and everything is setup for you out of box. In fact, it's a bit of a pain to break out of Kindle Fire portal and revert back to native Android.
OTOH, Google Nexus family of devices is targeted towards a different crowd. Nexus devices are comparatively sparse, receive latest updates, and not marketed at all.
With a Nexus 7, there's nothing stopping me from downloading the Kindle app and buying / reading my Amazon content. Try using a Kindle Fire to read Google Market content. If you've never used a Kindle Fire, you have to "jailbreak" out of the Kindle portal where they keep closing the holes.
OTOH, Google Nexus family of devices is targeted towards a different crowd. Nexus devices are comparatively sparse, receive latest updates, and not marketed at all.
With a Nexus 7, there's nothing stopping me from downloading the Kindle app and buying / reading my Amazon content. Try using a Kindle Fire to read Google Market content. If you've never used a Kindle Fire, you have to "jailbreak" out of the Kindle portal where they keep closing the holes.