Linux has won the server and HPC room war, there are many other kinds of deployments.
On mobile there is iOS and regarding ChromeOS and Android it is only an implementation detail, lets see where it goes if Google is serious about Fuchsia.
On game consoles we have a modified BSD on PS, Windows variant on XBox and Nintendo's own microkernel.
Then on IoT space BSD licensed OSes like mbed, Zephyr and RTOS are on the rise.
And then there is the whole mainframe and high integrity computing domains.
Not really, you missed the point that the Linux kernel is actually irrelevant for app developers on Android, to the point that ART might in the future run on top of Fuchsia and no one would notice.
There are no Linux kernel specific APIs in the list of stable NDK APIs.
You might naturally create an NDK application and do a bunch of syscalls, just it doesn't mean that the APK is guaranteed to work across all Android devices.
Of course Linux is an implementation detail. When did I claim otherwise? That actually proves my point: Fuschia is another implementation detail as well.
On mobile there is iOS and regarding ChromeOS and Android it is only an implementation detail, lets see where it goes if Google is serious about Fuchsia.
On game consoles we have a modified BSD on PS, Windows variant on XBox and Nintendo's own microkernel.
Then on IoT space BSD licensed OSes like mbed, Zephyr and RTOS are on the rise.
And then there is the whole mainframe and high integrity computing domains.