In an ideal world, of course you'd retain carriers and SHar. It's a capability.
But this isn't an ideal world and tough choices have to be made as to which capabilities have to be retained and which ones are less likely to be required, and which can therefore be (reluctantly) jettisoned.
As Proooone points out, we have NEEDED carriers only once in the last 30 years (you could prehaps say only once since 1956) though they have been 'nice to have' on other occasions, although they represent a massively costly and inflexible way of deploying air power.
The prospects of us needing organic air defence for some autonomous blue water operation against an opponent capable of presenting a viable threat (without allied support and outside the range of land-based AD) are remote.
Other capabilities, which are competing for funding with the SHar are required EACH AND EVERY TIME we do anything, even with coalition support. It's a hard decision, but at the same time there is no contest. SHar has to go, and carrier aviation should follow it.
Given Cold war funding levels I'd keep carriers, no question. But that's not what's being given.