The problem for the RN is that if the carriers go anywhere OTHER than on NATO ops they will have to be supported totally by RN ships - so a substantial part of the active fleet will be in one place around the carrier. Right now you are stretched all which ways with individual ships scattered from the Falklands to the Gulf
As an absolute minimum (assuming that opposition aren't going to use subs) you'd want a T45 and a frigate and an oiler so that means at least 2 current locations can't be covered any longer.
It's not that the Carriers are useless it's just that they tilt the RN away from the bread & butter operations they carry out 98% of the time to cover a highly unlikely hot war in which (TBH) the life of any carrier is likely to be very very short. They skew the budget, the strategy, the manpower in teh wrong directions
IMHO the best thing now would be to park them at Portsmouth next to "Bristol" (another white elephant) and allow them the occasional sail around the Isle of Wight on high days and holy days................