Curtail flying pay for those who have not flown for weeks?
I'd like to see your maths. Training pilots is expensive and we don't pay them particularly highly so retention is always a challenge. Pay them less and more will walk and your training bill soars. The entire cost of pilot RRP(Flying) is covered by the cost of training just 2 replacement pilots.
As for the 'waste' associated with the PFI for aircrew training, well just what made you think that any of the services thought that any of the costly PFIs were a good idea? Again, look towards the Treasury.