The point of an app store is to make money for the app store owner. The owner charges "rent" to put your app in its store. The rent is a cut of your earnings. So, given this fact - do you think putting Google Play on its Tizen would benefit Samsung? Because then the marketplace would still be google's and the revenue would still be theirs..

Amazon Marketplace is not Google play is it? So the revenue from it is going to amazon.

It is not allowed to use any part of Googles Services for Android on a non Android device.

Links: http://en.wikipedia.org/wiki/Android_(operating_system)#Lice... https://source.android.com/compatibility/index.html