Additionally, Apple has a long term roadmap to fix that design decision, hence why they are killing one kernel subsystem at a time, moving them into userspace, with one year given for the developers to adopt each of them, after being made available as the new way.

Finally, it is kind of ironic that systems that have doubled down on monolithic kernels, are now used to run an endless pile of containers and Kubernetes clusters.

The microkernel aspect of it had completely vanished by the time they hit the general public.

> i agree that monolithic kernels are unpleasant and brittle, but unfortunately they don't actually seem to be obsolete

Of course they aren't obsolete! The security in your phone depends directly on sel4, at least if you use an apple device. They just aren't relevant to most of the compute and most of the software you interact with today or in all of history.

Mach has basically always supported that kind of use, even back to early CMU research versions.