For doing what Haiku and BeOS excel at, you need a huge pile of patches to the Linux kernel, to rewrite even more subsystems than Android did -- for one, the au

For doing what Haiku and BeOS excel at, you need a huge pile of patches to the Linux kernel, to rewrite even more subsystems than Android did -- for one, the audio subsystem in Linux is an absolute disaster, and have the impedance mismatch of your kernel not being written with neither the same philosophy nor language as the rest of the OS. Haiku wants to be backward compatible with programs written for BeOS, so you'd have to write a mish-mash of compatibility drivers for that to work. At a point, it becomes easier to just write your own kernel.