Yeah this, really. For the most part even monolithic kernels have kind of reversed trend in the last decade or so and there's a lot of push to move critical cod

Yeah this, really. For the most part even monolithic kernels have kind of reversed trend in the last decade or so and there's a lot of push to move critical code out of the kernel. A lot of new kernel apis are built to avoid context switching, and part of that usually involves moving to a more asynchronous kind of communication between process and kernel. Often these APIs even look an awful lot like late generation microkernel shared memory buffer protocols. DRI and uring in linux for example. A lot of the "microkernels are inherently slow" meme is built on how earlier port-based message passing kernels like mach worked.