Why replacement warships keep growing

What causes replacement warships to increase in displacement?

The accumulated weight and volume of wider missions, modern systems, endurance, and future-growth margins make larger hulls necessary.

Blue-water endurance matters, but it is only part of the growth. A successor expected to combine anti-submarine and air-defence functions inherits equipment and support demands from multiple older types. Designers also need space, electrical power, cooling, computing capacity, and upgrade margin for systems not yet fitted at launch. High-speed missile defence further requires raw sensor data to be processed aboard the ship with minimal delay, preventing designers from simply moving all computation ashore or into satellites.