Why Britain was slower to adopt all-or-nothing armor

Why was the Royal Navy slower than the United States Navy to adopt all-or-nothing armor?

British designers expected battles, especially in the Mediterranean, where ships might not be able to maintain the ranges that made all-or-nothing protection most attractive.

British and American armor choices reflected different expectations about combat rather than simple resistance to an American innovation. All-or-nothing protection works best when a ship can preserve the engagement ranges assumed by its designers. Royal Navy planning included the confined Mediterranean, where maintaining that distance could be more difficult. Armor distribution therefore depended on theater, tactics, and how each navy expected its battles to be fought.