Shanny wasn't the head coach of the Falcons no matter how many people try to tell you he was. The team allowed Brady to drive up and down the field at will in the second half and in OT with very little resistance. They put up a lot of points on a Bill Belichick defense. It's not the same situation at all.
It was Shanahan's awful play calling that lost that game. They were up 8 with 4:30 to go when Julio Jones made an unbelievable catch to get them around the 20-yard line late in the 4th quarter:
Shanahan, then called a couple of pass plays. They got a holding call on one, and a sack on another play. Then, they were not even in position to kick a field goal. They punted. Then Brady marched down the field to tie the game.
During that second half, Freeman was running the ball effectively. Some times you have to play conservatively. His aggressive approach on that last drive in regulation was a major reason why the Falcons lost.