IMHO this is just an example of how military cuisine has evolved (maybe more slowly in some places) as transportation and preservation methods have changed.
My Dad was in the U.S. Air Corps (in WW II, before there was an Air Force). SOS was made with (dried, salted) chipped beef. If there was someone who gave a S running mess the dried meat was soaked to get some of the salt out and the SOS, to my Father’s taste, was edible. Usually it wasn’t.
Later on he’d make his own version that he’d still call creamed chipped beef with any leftover cooked beef laying around, and he’d make us kids eat it as dinner. Our inevitable response [xx(] led to extensive detail on the story above.
BTW – my Wife grew up eating the ground beef version as hamburger gravy on mashed potatos.