I have seen this happen in a real game once. Last year I saw Dunta Robinson do this to a HB in the backfield. that is one time in probably over a hundred games I have watched, which definatly justifies madden, and now head coach making these tackles occur like 30 times a game. Once every hundred or so games, 30 times a game, pretty close to realism right.
Another thing, this happens less in head coach than in madden but still way to much. a QB being tackled before he is able to hand the ball off. I have never seen this in an NFL game, and maybe a couple times in high school games. In head coach it happens ussually once a game. I mean think about it, on most run plays it takes less than a second to hand the ball off and other than some draw plays and trick plays never 2 seconds. Think about what this means that a DT would have to do in ussually less than a second. He would have to read the snap, get out of his stance, beat the olineman, get a yard or so into the backfield, and wrap up the QB to the point where he couldn't reach the ball out and hand it to a back. If and guard or center ever allowed that they would probably be benched on the spot.