After Britains' carrier force went into decline many other nations then in the carrier club lost their primary supplier of cheap second hand ships. Britain was and still is the world's largest exporter of aircraft carriers (Colossus/Majestic class and the odd Centaur class...), we invented the Stea Catapult, Angled Deck, Mirror Landing sight, Ski Jump, Jet Engine, Radar, the list goes on. And we gave it all away, including the ability to make most of the above. Smaller nations could only stay in the carrier club if they could replace their existing ships with more second hand ships. After WW2 the production of these ships effectively stopped. Britain completed what ships it could, and failed to build new until the 70s. When America stared building new, it built big, and their older ships were also too big for export (Essex/Midway class) or too obsolete in design (wooden decked like the Independence class CVLs, though one went to Spain in 67 as a helo carrier). Any nation wanting to get into the carrier game now will have to be able to afford a new ship, and that's too much for most.