Why not sweep British submarines more aggressively?

Why did Italy not devote more effort to sweeping British submarines from its waters?

A stronger antisubmarine campaign required many more escorts and the shipyard infrastructure to build them, which Italy had not developed.

Antisubmarine warfare depended on more than ordering existing warships to search harder. Italy needed a much larger force of purpose-suited escorts to protect routes and sustain sweeps. Building those ships required yard capacity and supporting infrastructure that earlier policy had neglected. British U-class submarine successes thus reflected the choice of prestige combatants over maritime systems.