Many people will be quick to point out that it Google is a technology Company with lot of products. However, Google at heart is Advertising Company.
Since Google gives away most of its products for free, it earns revenue through Advertising. Every product of Google revolves around this. Google has similar plans with Android and wants to put it everywhere. Android is now the most popular mobile operating system in the world. Android is on every device you can think of. Manufacturers save the trouble of building a new OS from scratch by simply adopting Android.
Everything related to Android is not under Google’s control; manufactures are trying to build their own OSs based on Android. Samsung unveiled a new Galaxy Smartphone with a custom app store, partially bypassing Google’s own software marketplace. On the other hand Facebook increased rivalry with Google+by introducing Facebook Phone and Facebook Home built on Android.
What Google wants loyalty from its Android partners and don’t want anything that will cut back their revenue stream from the devices. The 299$ Nexus Phone was an effort by Google to keep control of its own mobile OS. The new Galaxy S4 Nexus edition is a move towards the goal of having a pure Google ecosystem.