In practice companies are more likely to upstream non-gpl not less. With GPL they decide to use it without allowing any change, or they don't use it at all. With more liberal licenses they upstream anything that isn't core value because the cost of maintaining a fork is higher the more they are different.

GPL advocates try to claim otherwise of course.

I would be happily using HP-UX, Solaris and Aix to this day, so don't mistake my philosophical questions as a GPL advocate, just don't be surprised how the IT landscape will look like when GCC and Linux are no longer around.

Do you think there will be a possibility someday Linux will be replaced, both on Mobile ( Android ) and on Server?

I keep wondering if Microsoft opens up the Windows Kernel ( And Kernel only ), would it change the landscape much.

On the age of cloud based runtimes and OS agnostic containers, Linux is an implementation detail of the server.

On Android Linux is an implementation detail, most of it isn't exposed to userspace, not even on the NDK as Linux APIs aren't part of the stable interface specification.

And ART is being ported to run on top of Fuchsia as well (https://android-review.googlesource.com/q/fuchsia), so...