Aircraft development quickly outpaced carrier weapons

Why was the 4.7-inch anti-aircraft gun not used more widely?

It suited the aircraft threat when designed, but aircraft performance advanced faster than the gun and the ships carrying it could be replaced.

The Royal Navy's 4.7-inch anti-aircraft gun was credible against the aircraft expected when it was designed. Aircraft speed and maneuverability then improved quickly enough to erode that usefulness. Interwar aircraft could change much faster than the carriers and guns built to operate with or defeat them, because ships required far longer construction cycles. The watch point turns one armament question into a broader lesson about matching long-lived naval platforms to rapidly evolving air technology.