Why the counterfactual stops short of a wartime timeline

The machinery change begins in 1934, but German, Italian, and Japanese responses would quickly create further divergences. Those navies might pursue higher-pressure plants of their own, alter ship designs, or redirect limited industrial capacity, and the timing of their reactions cannot be established from the premise alone. The analysis therefore concentrates on British and some American construction choices before the war, the part that follows most directly from the changed machinery. Later operational suggestions remain conditional, while the prewar fleet changes can be evaluated on firmer ground.