This is missing the point. The point is that if functionality is core to what you are doing with your OS, then it ought to be a core part of that OS and not la

This is missing the point. The point is that if functionality is core to what you are doing with your OS, then it ought to be a core part of that OS and not layered on top. If that would make the kernel of your OS too big and too complex then the design of your OS is wrong.