[makomk]

At the moment I'm using OpenRC which does exactly that on top of sysvinit, as are most Gentoo users. You don't have to specify everything twice because init never actually knew how to start and stop services in the first place - with a traditional sysvinit configuration that was all handled by scripts that it started, and OpenRC replaces those scripts.

[the_why_of_y]

sysvinit does have built-in service management via inittab(5); unfortunately it is so primitive that in practice it is only used to spawn getty(8).

[JdeBP]

> unfortunately it is so primitive that in practice it is only used to spawn getty(8).

The AIX System Resource Controller is spawned by a record in /etc/inittab. (AIX actually comes with utilities for maintaining /etc/inittab such as mkitab.) So too is svscanboot in daemontools 0.75 and later. Gerrit Pape is currently having problems with the Debian package for running runit, precisely because runit has for some years been run from /etc/inittab in some configurations and in Debian 8 it is suddenly no longer a file whose existence is always guaranteed because it is part of an "essential" package. There are some other packages in Debian 7 that have undocumented dependencies from the existence of an /etc/inittab file, because they too read/write it for their own purposes. I have yet to verify whether they've been fixed for Debian 8.

Don't think for one second that in the second decade of the 21st century people only ever use /etc/inittab for getty. (-:

This is one of the quieter on-going problems for Debian 8. It switches one to using systemd, because that's the Debian 8 default; but there's no upgrade path or compatibility mechanism for /etc/inittab. Every few months, another "I was (unknowingly) using /etc/inittab; I upgraded; it broke." person seems to pop up.