Of course you were wondering. In that little bubble you inhabit, no officer ( of the useless variety ) has ever been posted sideways into one desk job after another until they reach the 16 year ( pension ) point, and then quietly disappear. ( There is certainly scope for civilianising those desk jobs )
Does the same thing happen ( with useless ) OR's ?
If the answer is no. Then
@bob231's assertion is absolutely correct. There is a major issue with a career structure that holds onto ( until pensionable ) useless officers.
The difference between useless officers and WO1's & WO2's, is that while some are absolute c**k's, very few of them can be regarded as useless, or they would never have reached the rank of WO1 or WO2.
** With the caveat that the R.Sigs might be totally different from the rest of the British Army.