Which seems particularly odd because (unless I'm hallucinating again) the comm panel on the MD-10 which I understand was carried forward from the DC-10 so similar "root era" has a PA knob so it wasn't something that no one thought of.

I can't remember ever thinking the PA was too loud but the number of times I've barely been able to hear flight deck announcements is far greater than the number where it's been just right (one of my flights last week the only reason I knew the FD was trying to do a PA was the seat back popped the "PA Announcement In Progress" message on screen but nothing at all was heard)