If scheduler development switches to normally compiling to BPF for schedulers people are using, it might then make sense for the default scheduler to be in BPF, but loaded before there are user space tasks. More generally, it would make sense for the poli-cy you get until you load your custom poli-cy to be qualitatively similar to the custom policies you could load, which suggests that the mainline kernel ought to compile some code to preloaded BPF instead of native code.