The userland and kernel are developed together by the same group of people/project. So the design is consistent across the system. In Linux the kernel comes f

The userland and kernel are developed together by the same group of people/project. So the design is consistent across the system. In Linux the kernel comes from Linus and the kernel development team. The userland usually comes from the GNU core utils team, the distro creator and several other places. This can cause disconnects between how various things in the system work, kernel patches to get a random features to work, etc.