"Instead of either scrapping the aircraft or selling them to museums or people who want to put them in car parks, why not put some aircraft into storage, complete with engines and avionics, so that they can be brought out of mothballs if needed."
Because you'd need to retain a great deal of infrastructure, spares, manpower etc. and wouldn't be able to leverage the savings which a complete retirement would achieve.
And because they NO LONGER FULFILL A MEANINGFUL ROLE.
1) You can't fit enough of them on a CVS to give adequate AD cover, and by trying to do so, you reduce the number of GR7/9 embarked and thus you inhibit the CVS' usefulness in the A-G role.
2) Didn't you read what Moe Syzlak said?
Let me remind you: "I did Deny Flight from a CVS and we were only playing at it. The FRS1 was not really capable in theatre (1 got shot down for his trouble) and the mission was, primarily, one of flag waving. The FRS2, latterly FA2 had a much better air to air capability-as has been hammered to death here- but the same air to ground capability and as such was a day,vmc,permissive platform-NOT useless, but limited. Over and over again a capability or readiness would be declared to wave the flag but,also, in the fervent hope that the HQ did not "press to test" and expose the reality. Ship based aviation is great when there is no other option-THAT is the raison d'etre. But to plug away for years 30 miles from Bari et al erodes the argument and morale (see PVR rate!!). There was always other ground based assets to cover any fogged in at Gioia-and even then they could launch in fog if the mission was important-then land elsewhere. That cannot be said for an FA2 on a ship in dock at Palma with half the CAG on the pi$$....."
And because they were knackered and fit for the scrap heap. Did you note the Flight report that reported a reduction in fan blade life from 500 to 90 hours, or the 43 engine changes in the last 18 months rather than the five planned? Were you aware that the SHar in its last year of service required more MMH/FH than any other type in UK military service? That the SHar's MMH/FH figure was higher than that for the USN's F-14s?