Unstable kernel ABI gives the Linux kernel enormous leverage: device makers either upstream their drivers under the GPL or they get left behind.
Stable userspace ABI gives people like me the complete freedom to build anything on top of Linux. I can just discard stuff like glibc and build my lisp user space for the fun of it. Rust programmers can do the same.
Unstable kernel ABI gives the Linux kernel enormous leverage: device makers either upstream their drivers under the GPL or they get left behind.
Stable userspace ABI gives people like me the complete freedom to build anything on top of Linux. I can just discard stuff like glibc and build my lisp user space for the fun of it. Rust programmers can do the same.