Hello

> I come from a Unix background -- separate /usr was deprecated in the 1990's
> with SVR4.2, I'm kind of amazed it took Linux so long to catch up.

Clearly I must have been working in a parallel universe - the
commercial unix systems that I remember from the 90s did have
/usr and / (some also had /opt and /usr/local in various forms)

But regardless of this, what you are doing here is called an
"appeal to authority" and so of limited relevance.

Having a small safe userland to boot up the full system allows
one to recover from a number of mishaps and permits complex
startup routines. In the past this was separated out with /
and /usr, now most of the startup logic lives in an opaque
mess called initrd/initramfs which every distribution hacks
up in its own so special way. I don't regard this as progress.

A wiser decision would have been to merge the initramfs with
/, so that / could optionally live in RAM and linuxrc can be
normal init right off the bat - that would allow one to eliminate
the complicated and brittle mess that we know as mkinitrd.

Yes, /etc would need to be made persistent somehow. That would
still be simpler than the current mkinitrd. If done smartly it
would even allow one to have a "safe" /etc version permitting
rollbacks from config finger trouble.

regards

marc