Why destroyer mass did not replace a balanced fleet

Would a navy be better served by 100,000 tons of cruisers and destroyers than by dreadnoughts?

Not as a universal rule; a balanced mix of capital ship, cruisers, and destroyers is more reliable than assuming a mass destroyer attack can always be assembled.

A 100,000-ton allocation could buy battleships, cruisers, destroyers, or a mixture of all three. Sixty-six destroyers would be dangerous when massed, but capital ships might operate where only part of that flotilla could reach them or fight effectively. A mixed allocation supplies heavy firepower, scouting and screening, and torpedo attack without relying on one ideal concentration. The Royal Navy and US Navy came closest to planning capital ships, carriers, cruisers, and destroyers as an integrated procurement programme.