The problem with cutting headcount (either as a positive measure or by neglect leading to natural wastage) in the RNR is that the focus on RNR Training Centres as the core means of maintaining cohesion and administering the Reserve is a very expensive way of doing it (even with cost sharing among RNR, RMR, URNU, AFCO, Uncle Tom Cobley and all).
Once numbers drop below a critical mass you might as well draw stumps across the whole lot (standfast a couple of skill areas that tend not to be Unit-centric in the first place eg FAA, Int, Media etc)
The big problem is Q- "When is a Reserve not a reserve?" A - "When it is being used". The NEED at the moment is boots on the ground so the TA, RMR, RNR, RAuxAF etc are all being used and the cost-benefit equation of maintaining the Reserves as before is even less attractive to the bean counters who have immediate short term worries that far outweight the longer term ones.