I think this may sound crazy but android's days as a apremium OS are not as secure as they seem. Take Samsung out of the android picture and you will see that there is barely any device maker that is leading charge.

Add to that the pressure brought on by Microsoft which runs almost the same version of OS on its phone and PC. This will allow them to innovate much faster. Google wants to be there. So even though the brand name will stay, Android as n OS will evolve to what is Chrome today. Completely controlled by Google.