Did the lack of high-angle destroyer guns reflect the limited dive-bombing threat of the 1920s?
Short answerNo. Dive-bombing already existed, but the Air Ministry promoted level-bomber assumptions and exercises repeatedly directed aircraft at capital ships rather than their destroyer escorts.
NotesDive-bombing had been demonstrated with biplanes, yet the Air Ministry argued that strategic level bombers would be the decisive threat to ships. That position also protected the case for an independent air service built around strategic bombers. Fleet exercises reinforced the error because attackers concentrated on capital ships, leaving escort destroyers to fire across the formation at relatively low angles. Reality overturned the resulting assumption that destroyers themselves would not face steep diving attacks.