Why the alternate treaty does not cap battleship speed

Why not impose a speed limit on battleships in this version of the Washington treaty?

Because speed caps were not part of the contemporary Washington framework, while displacement already forced designers to trade speed against armour, armament, and endurance.

The counterfactual changes one disputed category while retaining the period's negotiating habits. A direct speed ceiling would import a later form of restriction into a conference that relied primarily on displacement and gun limits. Designers can still pursue faster ships, but they must pay for speed within a fixed tonnage envelope. That constraint preserves the historical design tradeoffs without adding a rule the delegates were not yet using.