On the face of it, it might seem that there are too many VSOs for the size of the air force, ditto other services but there are some good reasons for this apparent abundance. Some of the reasons have been touched on already.
There is the obvious one that you need 25X in order that 35 years later 1X pops out the top. There is an international equivalence to be considered and hence an apparent over promotion. The complexity of the modern services requires appropriate remuneration and the only way seen to do this is by advancing rank (it might be that some people could be paid a premium without promotion – a sort of Branch Officer/specialist setup for higher ups). We still seem to have a pyramid of 3 times A reports to 1 times B but then 3 times B report to 1 times C etc.
In about 1994 there was a study undertaken to consider ranks, rank skipping and one or two other things, including doing away with some ranks entirely but as long as those most likely to be affected are probably the same people who will decide the study’s outcome, it won’t happen. The only outcome of the 1994 study was that Marshals of the RAF wouldn’t normally feature!
Old Duffer