Why 40 mm Bofors guns could persist without missiles

If missiles had never appeared, what would replace 40 mm Bofors anti-aircraft guns?

Probably nothing directly: 40 mm guns would remain, while 76 mm weapons might become more common.

The counterfactual asks what would replace the 40 mm Bofors if missiles never became available. The gun would likely persist because navies still retain weapons of that size alongside modern systems. A 76 mm anti-aircraft gun might become more common and offer a different set of advantages. The likely result is a broader gun-based air-defence mix rather than wholesale replacement of the 40 mm weapon.