How class commonality makes modernization affordable

Would several Renowns have been too difficult to modernize in the 1930s?

No. Standardizing the fleet around fewer designs would make modernization easier because solutions could be copied across sister ships.

The 1930s Royal Navy faced separate modernization problems for the Queen Elizabeths, Revenges, Renowns, and Hood, including differences within classes. A fleet concentrated around fewer designs could develop two repeatable programmes rather than four bespoke ones, saving design capacity as well as dockyard time.