I had experience of several sides of a pretty-odd-shaped-coin during my time in the military. Combined messing at small stations like Watton and Byron, avoiding sitting at les pompiers table at Le Luc, crew tents and all-ranks 'dining' during GW1, officers-only aircrew crewrooms on board the grey-funnel-line, being served Christmas Dinner (as a squaddie) by the Wuperts then doing the same for the 'chaps' years later... However, anyone thinking that the subject-under-discussion is purely a military matter is mistaken, as goudie and others have suggested.
These days I have the privilege to work for a customer that operates 2 working vessels on duties primarily around the northern part of the British Isles. When the newest of those 2 ships was on the drawing board, the customer had to seek permission from the DTI to include combined messing in her design. A previous ship operated by the same people as recently as the 1970s had up to 7 messes in use at any one time. However, far from snobbishness and feudal custom, the reason this permission had to be sought is that the DTI had to be satisfied that the members of the ships crew would have enough time and space away from supervisory grades to be able to relax when not on duty. Morals and socialism don't factor - maintenance of a happy, functional and efficient ship and crew is what it's all about.
As for people living in accommodation/ owning stuff they can't afford - that's probably part of the reason we find ourselves in our current financial straits, no?
BEags, were you and another ex-Bucc mate cycled through N Luffenham around Sep 1976? Might've met you when on my initial AMTC course.