Why better ship-to-shore plans do not create an early D-Day

What changes if Britain and the United States solve ship-to-shore logistics early in the Second World War?

Less than expected unless they also build the equipment, train the forces, and secure air superiority; landing technique alone cannot make an early invasion viable.

Many ship-to-shore concepts were already understood in the 1930s. The slower work was building landing craft, training armies, positioning forces, and shaping the battlefield. A hypothetical 1943 D-Day shows why better unloading methods alone would not protect landing ships while the Luftwaffe remained effective over western Europe. Operational timing depended on air superiority and accumulated capacity as much as on amphibious doctrine.