Continuous construction as industrial deterrence

The counterfactual broadens from carrier totals to the industrial effects of arms-control rules. Continued Allied construction would preserve shipyards, design experience, and successive generations of modern ships rather than allowing capacity to atrophy. Continued Japanese construction would also leave room for planners to hope that qualitative improvements could offset numerical inferiority, giving them a reason to remain within the system. Germany and Italy would then confront a Royal Navy whose fleet and construction base looked much harder to overtake, changing the deterrent calculation before war began.