You really are missing the whole point of the Royal Navy aren't you.
The carriers are defended by air defence Destroyers, anti-submarine Frigates, minesweepers and hunter-killer boats. The embarked air has the task of providing an extended defensive screen (or in the case of Sea Harrier, not so extended).
The carrier has the task of providing a sea-borne base for the embarked air, a rally point for all the other ships and a fall back location for diplomatic cocktail parties.
Phalanx and goalkeeper just ruin the aesthetic lines intended by the ship designer.
I trust this clarifies the matter.