Look at this story as another in a series of extreme efforts in 1943/1944 leading up to D-Day, the absence of which could have resulted in a different outcome. The portable Mulberry harbors. The Higgins boat. Operation Fortitude's ghost army. Juan Pujol's network of fictitious German agents. And even with all of those efforts, had Hitler decided to move Von Schweppenburg's panzers, D-Day would likely have failed.

So yeah, again, the title is a bit breathless, however it's not a stretch to say that much like at Incheon getting the tidal flows wrong would have significantly altered history.