Political Will
Without stirring the pot too much, it is possible carrier aviation declined when Air to Air refueling became generally available. The need for force projection has become an American thing which is why they are the only ones who maintain (or can afford) a large carrier fleet and is therefore not global anymore. Even they sometimes don't use carriers for certain objectives.
e.g. The libyan raids were done by ground based bombers flying from England with air to air refueling.
In Britains case it was political will that dealt the death knell for our carrier fleet.