Why late-war US carriers carried more fighters

Why did US carrier air groups shift from roughly equal fighters and dive bombers toward many more fighters?

Air-defense demand grew, while fighters became capable fighter-bombers that could replace many dedicated dive-bomber sorties without adding aircraft beyond the carrier's capacity.

The Japanese Navy offered fewer targets that required dedicated dive bombers as late-war fleet air defence grew more urgent. Fighters could attack destroyers with 5-inch rockets and carry bombs for other strike and troop-support missions. Corsair squadrons could replace dive bombers while retaining a similar bomb-carrying capability. A carrier had finite space, so expanding the fighter force displaced some dive bombers while also improving defence against the growing kamikaze threat.