Why submarines were a poor answer to fast battleships

Would the Francesco Caracciolo class prompt earlier refits for ships such as Hood or a larger submarine response?

Possibly earlier capital-ship responses, but submarines would struggle to prosecute fast, zigzagging battleships; torpedo boats or destroyers are more credible counters.

Area-defense submarines are poorly suited to hunting fast capital ships. A battleship that changes course at speed is difficult for a submarine to reach and place inside a firing solution, while motor torpedo boats and faster destroyers can react more directly. Treaty limits on submarine numbers would also constrain a large counterbuilding program. Without those limits, an Italian N.31-type destroyer response might trade some armament for additional speed.