Because it's work, for no apparent gain. I mean, the systemd people
didn't
just code up all that journal stuff for no good reason, but because
they
perceived a need to have it. And let's face it, the ability to just see
the
stderr output from $FAILED_JOB with "systemctl status" is a whole damn
lot
better than to restart the thing in the foreground and hope to be able
to
reproduce the problem that caused it to die.
You can split off systemd-journal and its supporting files into a
separate
binary package. That'd probably be quite simple. The question is, why
would
you even want to ..?