Why helicopter ASW and V-22 delivery replaced fixed-wing roles

Why has the US Navy shifted from S-3 and C-2 aircraft toward helicopter ASW and V-22 carrier delivery?

Cost, aging-airframe maintenance, fewer supply chains, and the ability to serve many ships make rotary-wing and tiltrotor solutions more flexible.

Helicopters and tiltrotors can provide useful anti-submarine and delivery capability across more ships in a task group. A V-22 can serve ships that cannot accept a C-2, while improved rotary-wing capability has reduced the need for a dedicated fixed-wing aircraft in some roles. The ageing S-3 also carried substantial operating and maintenance costs. Using larger common fleets reduces the number of spare-parts streams needed by a deployed force, and avoiding arrested carrier landings reduces airframe wear. Cost is the main explanation, although an eventual return to an S-3-like role is left open.