The Zero was very manuverable - at about 180 IAS. By 225 it was getting very stiff, by 250 it was a total dog.
Starting with the F6F, US fighters were designed to simply fly faster than the Zero could be competitive. The F6F was simply designed to fight at speeds of 250-275 IAS, which was sufficient to ensure it had all the advantages over the Zero. All the Zero could do was turn, and in doing so it lost speed and energy, giving even more advantage to the enemy who would simply zoom off and come around for another high speed pass. The Zero's were pretty much helpless as long as the Allied pilot did not actually slow down and try to turn with them and stay on their six.
The F4U was a carrier plane, it just took a while (and some innovation by the Brits) to develop the techniques needed to use it effectively as such. By late 1944, the Corsairs were operating off Carriers quite effectively.
=S=
Lunatic