While it is true Android is becoming popular to the point of virality. The Android software is more kin to a Window manager or "App dock" than an OS. By definition an OS is responsible for the key underlying functionality of the hardware. While many Android developers and hardware vendors implement many wide ranging customizations to the Linux kernel. Those changes are hardware specific to device and the java machine running Android on top of that, will mostly still operate normally or even run on an unrelated and different machine altogether perfectly fine, without changes.
