[nradov]

As the threat had evolved, the US Navy has started phasing out the Phalanx CIWS and replacing it with various RIM-116 (RAM) launchers. These are much more capable against high-speed maneuvering targets.

https://navalpost.com/searam-ram-vs-phalanx-goalkeeper/

But realistically the limiting factors for point defense are more likely to be detection and engagement range rather than magazine depth. Hence the focus on layered air defense including longer range missiles, countermeasures, and decoys.