Why did the Royal Navy not adopt V/STOL earlier?
Short answerWhile CATOBAR was affordable it provided heavier, more flexible aircraft and fixed-wing support types; V/STOL became attractive when Britain needed a cheaper system it could still sustain.
NotesA CATOBAR carrier can launch heavier aircraft with more fuel, sensors, and payload than a short-takeoff design. It can also operate fixed-wing airborne early-warning and specialized support aircraft that broaden the entire task group's capability. Those benefits require a larger ship, complex machinery, trained deck crews, and a costly support system. Britain turned to V/STOL when it could no longer sustain the full arrangement, not because naval planners had previously failed to see vertical flight's potential.