I remember your boss's era quite clearly Peter.
Yep, average size back then was 6" but if you had an 8" you were classed as 1 rung up the ladder from the norm. If you had a 10-14" Well! you were in a league of your own almost.
I dreamt of having an 8" when I was 12 & by the time I was 13 I ended up grinding an 8" & building the rest between me & my dad.
Those were great times back then, flipping thru Sky & telescope & Astro Optical Supplies Celestron catalogs & the likes, & seeing those HUGE 8 & 10" SCT's etc.
I reckon today the norm, or average size is 10"