Could large numbers of sloops have threatened enemy capital ships?
Short answerNo. Their four-inch guns were unsuitable against battleships; their real value was anti-submarine warfare, convoy escort, and merchant-raider defense.
NotesA mass of escorts could not substitute for a battle fleet. A battleship placed among four-inch-gunned sloops would destroy them because the smaller ships lacked the weapons, protection, and purpose for capital-ship combat. Their value lay in anti-submarine warfare, convoy escort, and action against converted merchant raiders. Failing to build enough sloops was therefore a mistake: the type already existed, Washington left construction open, and a program begun in the 1920s could continue under the later London rules.