Destroyers grew out of torpedo boats as naval roles and ship sizes changed. Cruisers were expected to spend more time operating independently around the world, maintaining a presence and carrying out imperial policing. Those expanding requirements widened the gap between cruisers and small torpedo boats. Escort and screening duties created a role for destroyers within that gap. France's industrial focus on torpedo boats and large cruisers had left weaknesses in the infrastructure needed to build the intervening types.
Notable Point · 4:50-5:44
Why destroyers grew beyond torpedo boats
As cruisers took on more independent global patrol and imperial policing, destroyers filled a widening need for smaller escort and screening vessels.