Phil_R,
What exactly do you mean by "..a differentiation between officers and other ranks.."?
Are you referring to:
Pay
Conditions, e.g. housing/messing/postings/office space...etc/etc
Qualifications
Responsibility
Selection
Etc
Etc
All of the above?
Are you seriously telling me that in civilian life there is no "differentiation" in at least some of the above list (e.g. pay/office size/perks/etc) between the very top and the very bottom in most companies?
Perhaps I'm being a bit thick today - it wouldn't be the first time, but I'm not quite sure what your exact point is? Are you just referring to some concept of perceived social status?