Later hull technologies offer a straightforward advantage in the Hearts of Iron IV example. Accelerating research can put a nominally much later design into production years ahead of its label. The example imagines a 1944 hull becoming available around 1939-1940. That is a game progression result and should not be read as the historical readiness of an equivalent ship design.
Notable Point · 3:45:48-3:46:18
Hearts of Iron IV hull progression and historical ship design
The game example lets a player accelerate later hull research, illustrating how technology progression simplifies ship development.