The answer to the assumptions you make in your question, as hypothesis, is no: Were navies built around the use, and defense, of carriers from the start of the war?
About some weapons being more important than others in a pre-war state, I suggest to everyone to look at today's discussions about weapons. The main speech is "everything is important and we don't sacrifize anything, no no no". But in reality, obvious important weapons are made superior to some others, sometimes accurately, sometimes no. The point here is that tactical guidelines, also known as doctrine, lacks the capability, especially in technical armies such as air force or navies, to provide clear elements on what is important and what is important but secondary.
This is general consideration. Now, answering to your question for navies in ww2 and how they considered carriers:
- Germany, Italy, Soviet Union: despite some projects, all these navies had not the opportunity to develop large fleets. They did not consider carriers important since their navies were supposed to operate under land-based air cover. USSR considered the navy as a support for land operations, so it was supposed to be close to the coast and covered by land air force. Italy did not assess correctly the danger of airplanes, and after "facing it", they relied on their land based air forces (some projects of carriers did not come to an end). Germany had two philosophy: first one planned destroyers and battleships to fight under air cover, and second one planned heavy cruisers and fast battleships and submarines to attack the trade without any air cover. The problem is that they did not respect this duality, such as for the Bismarck
- France: Similar to the others, but they developed some carriers to support fleet of cruisers in the colonial empire
- United Kingdom: Carriers had far more importance there. They were supposed to be used as the center of submarine-chase groups, and they were. It was also known they could attack ennemy ships, but their small air group made them only hit-and-run weapons
- USA: They definitely consider carriers as a weapon for line battle, but they were supposed to cover the battleships and help to attack, rather than be prevalent... what they in fact were during WW2
- Japan: Similar to the USA but the Japanese did consider the capability of carriers to attack as stand-alone fleets enemy forces, especially light surface forces and bases