As everyone sifts through the rubble of Gotham after retaking the city, it quickly becomes clear that the Tumblers used by Bane's forces were manufactured by Wayne Enterprises. They're all the same, precise design as Batman's supercarsuper-car...it becomes public knowledge that the Bat was Wayne technology as well.
Batman (apparently) died, Bruce Wayne disappeared...how can anyone doubt that Wayne was Batman? Plus, Batman showed up just as Bruce Wayne reappeared. I can see how you might miss that at the time, but in retrospect...plus Coleman Reese, now no longer necessarily bound by gratitude to Wayne....
Is there another angle to this, or is it utterly clear to everyone in the world who Batman was?