The video's counterfactual does not deny the danger of a stronger early U-boat offensive; it argues that timing mattered because Britain had three years to adapt by 1917. New sloops, corvettes, other anti-submarine measures, and merchant construction were responses enabled by Britain's maritime infrastructure. A force like the 1917 submarine fleet might have produced a very different result in 1915, although the claim remains explicitly counterfactual. Unrestricted attacks on merchant ships are also described as morally unpalatable, preventing the operational thought experiment from becoming an endorsement. This is a useful watch point on the difference between possessing a weapon and using it before an opponent has developed an effective counter-system.
Notable Point · 49:00-51:47
Why a 1917 submarine campaign faced a different Britain
By 1917 Britain had learned, built escorts, and expanded merchant shipping, making the submarine threat harder to exploit than it had been in 1914.