There's more to the platform wars than mobile - Android is starting to take off in non-mobile markets in a massive way - Internet of Things, Television (Chromecast), etc. To date Linux has been the dominant OS but Android is now taking some embedded designs which would have run Linux. The effective decoupling of Android from carriers for non-mobile markets + the richness of tools and the existing developer ecosystem will likely cement Android as the definitive open source OS of the next decade. This will have pluses for Google but also unintended consequences.
Repeat after me: Android is just as much 'Linux' as Ubuntu, Debian, Red Hat, or anything else that uses the Linux kernel. Technically, a better term would be 'Linux distribution', since Linux in and of itself is just a kernel. Wikipedia defines 'Linux distribution' quite well:
A Linux distribution (often called distro for short) is a member of the family of Unix-like operating systems built on top of the Linux kernel. Such distributions are operating systems including a large collection of software applications such as word processors, spreadsheets, media players, and database applications. These operating systems consist of the Linux kernel and, usually, a set of libraries and utilities from the GNU Project, with graphics support from the X Window System. Distributions optimized for size may not contain X and tend to use more compact alternatives to the GNU utilities, such as BusyBox, uClibc, or dietlibc.
Android is a Linux distribution, and is an addition to the Linux ecosystem - not a challenger. Painting it as such is just a sign of ignorance.