What made Trafalgar decisive

Trafalgar did not end the War of the Third Coalition, which continued into 1806, or remove every French naval threat. Britain still had to blockade ports, escort convoys, and carry supplies for armies operating ashore. The battle was decisive because the loss of ships and trained officers made a renewed French invasion threat far less credible even after Napoleon began another construction program. Its effect was to prevent a strategic danger from regenerating while many tasks at sea continued. Steam fleets could disengage under their own power, as Jutland shows, so decisiveness no longer required a Trafalgar-scale tally of captured ships. Midway, Cape Matapan, and Operation C offer more useful patterns for later warfare. Trafalgar remains something to study and emulate in principle rather than mechanically repeat.