This game had a very lowkey release. Even on release day, I couldn't find it at any nearby Walmart, and every employee just looked at me dumbfoundedly as if they had no idea what I was talking about. I eventually got someone to go into the back room and pull out a copy, so they had them but didn't even bother to place it on the floor.
You could also argue the title isn't very good or eye-catching, the game has been poorly marketed, and it's out during a crowded season. It's a fantastic game overall, so hopefully it does indeed become the sleeper hit some folks are saying, as I would love to see Ubisoft tackle another game in a similar way.