Tillman designs and a qualitative arms race

Would ships such as Yamato, Bismarck, or the Royal Navy's N3 have developed the same way if the United States had built Tillman IV-2?

Probably not. Britain would likely answer with faster ships carrying fewer but larger guns, potentially twelve 18-inch weapons, instead of copying the American arrangement.

The huge Tillman concept would open a qualitative competition rather than remain an isolated American super-battleship. Britain would invest in infrastructure and pursue battlecruisers with 16.5-inch guns alongside battleships carrying twelve 18-inch guns. The Royal Navy might try to build two useful ships against one American giant. Greater speed would let those ships control the pace and range of combat. One extreme design could redirect foreign requirements and dockyard investment across the entire arms race.