After daily driving OpenBSD and FreeBSD, i can point the finger at the kernel subsystems that tries to handle everything under the sun, but with no clear direction and competing projects with different designs. Everything is three or more layers, each governed by a different team and interacting in opaque ways.

Meanwhile in the *BSD, you have the devices or some other OS concepts/subsystems, then a control layer with the associated management tools. Any other tool is either an alternate version, or a UI paint job.