Why navies build very large warships

What real-world advantages do large ships have over several smaller ones?

Large ships can concentrate scarce expert crews, carry heavier weapons, provide stable firing platforms, and avoid multiplying some industrial bottlenecks.

A navy cannot assume an unlimited supply of trained specialists, so several smaller ships may demand more key personnel than one large hull. Larger ships can also carry larger guns and offer more stable firing platforms. Equal displacement does not mean equal industrial effort because four ships multiply requirements for propellers, turbines, and other complex machinery. Armour and structural steel may be comparatively easy to expand while turret and propulsion production remain bottlenecks. The comparison must therefore follow scarce people and components rather than treating tonnage as interchangeable.