The return of larger naval anti-aircraft guns

What would bring larger anti-aircraft guns back to ships as a response to missile saturation?

Their return is already under way through 40 mm, 57 mm, and 76 mm systems.

The return is already visible in 40 mm, 57 mm, and 76 mm mounts. These calibres provide a gun-based response to missile saturation and other close threats. Their adoption shows that the comeback does not depend on restoring an older cruiser-scale anti-aircraft battery. This is a developing trend, and navies need not converge on the same solution.