Hi,
in which sense not reasonable .
You write about TC early days, and it comes to my mind DSL, since the old TC users where before DSL users.
In DSL there was the possibility of an HD install.
having a persistent FS are you sure tce.installed scripts should be executed? Only the 1st time they are installed I think.
sces could be persistent using a copy2fs or not.
an fs=xxx boot option could be added, and if there is already the filesystem on the partition it's used otherwise the FS will be created
sce-remove will then unmount or delete the files (I know purists don't like this).
modern DE (programs) take care of starting system process they need, f.e. pulseaudio, dbus, wpa_supplicant, policykit.
Maybe we should look on the DSL installer script.
Maybe is the very hot weather of this days here in my country which makes this thoughts