Moot? Putting dbus in the kernel is demented. Creating a hard dependency between it and a monolithic set of interdependent systemd code is even more demented.
It's like the Linux folks looked at Mac OS X and learned nothing.
Hint: Mac OS X handles more that systemd does, and still does it in a way that maintains separation of concerns between service management, configuration management, logging, and IPC.
"Disconnecting from dbus" at that point will not be very meaningful.