Apple removed third-party kernel extensions (and even so only removed the ability to install them without going into recovery and changing a scary box). There are still lots of .kext files in the /System folder for hardware drivers.
Yes, however that brings it closer to a micro-kernel model, if no one else is allowed to change the kernel as shipped from factory, having everything else done in userspace.
Additionally, if there is a userspace extension to an existing kernel extension, the userspace one will take precedence.
https://fahrplan.events.ccc.de/congress/2007/Fahrplan/attach...
https://www.amazon.de/-/en/Mac-OS-Internals-Approach-paperba...
If anything it is going more into that direction, after Apple announced removing all kernel extensions, and having userspace counterparts to them.
https://developer.apple.com/documentation/SystemExtensions
https://developer.apple.com/documentation/systemextensions/i...
Usually it takes one OS version between introducing new userspace APIs, and removing the old way on the following version.