sysvinit was seen as legacy way before SystemD became a thing and there have been multiple previous attempts to replace it (i.e. runit). If you're solely relying on the logs on the local server, then you're already doing something wrong in the first place, at least at minimum have a proper syslog server and forward your logs, if not getting something like Splunk or ELK. Grep is great but using it for say scanning 1GB+ log files on a loaded production DB server is just a no, very bad practice.
you can still use text based files in systemd for launching services/daemons but the issue is that this really gives no real comprehension of process state and that is problematic in a professional enterprise environment, which is part of the reason why sysvinit really is legacy. Also the whole single threaded initialisation process and multiple other issues, since sysvinit has no real comprehension of dependancies either.