Merchant shipping without a Liberty-ship emergency

Would a delayed war replace Liberty ships with Victory ships?

No. Without a wartime emergency, merchant construction stays closer to normal patterns, although active shipyards could still turn out more modern merchant tonnage.

Peacetime does not create the emergency mass programme behind Liberty ships or advance Victory ships by several years. Shipyards busy with naval orders would still be motivated to work at capacity, so merchant construction could grow and benefit from improved turbine technology. The result is gradual commercial output instead of a wartime rush to replace losses.