Why conventional submarines still matter

Western navies can over-focus on nuclear attack submarines even though conventional submarines remain far more numerous worldwide. Most states operate SSKs, making them a more likely opponent in many conflicts than an SSN. Their lower purchase cost, smaller crews, and lighter training and maintenance burden let regional navies field useful numbers. An SSN is well suited to rapid movement between distant theatres, whereas an SSK can be highly effective in a home region, enclosed sea, or chokepoint. Judging both types by the SSN's global-deployment mission therefore makes the conventional boat look weaker than it is. Extra-large uncrewed undersea vehicles recover some of the same local-defence logic. Calling them uncrewed vehicles also lets budgets pursue that capability without presenting it as a direct challenge to the nuclear-submarine fleet.