Should navies revive massed 20 mm fire against drones?

Should navies bring back high-volume 20 mm anti-aircraft cannon fire to counter drones?

Only if it compares well with the alternatives and can be implemented cost-effectively; the weapon choice cannot be separated from practical fleet constraints.

Maturing drone threats do not by themselves justify bringing back high-volume 20 mm anti-aircraft cannon fire. The weapon must be compared with other available defences. Cost and the practical difficulty of putting a system into service also matter. The question leads into the later comparison of lasers and the high-low fleet mix.