Yeah, I thought about that example, actually, but didn't know how many would be familiar with the fight scene.
There's a theoretical point where skill can still overcome sheer mass, but there is absolutely a point where that balance tips. Had a friend who worked SWAT for several years and he came across more than one would-be kung fu user. He said if the person was unarmed but trying to use martial arts to resist, that he'd just bull rush (6'4", 275lb) the guy and drop him to the ground like Jason Peter. This was back before tasers and other non-lethal weapons were much more commonplace.
But back on football, a center who's 25lbs smaller than a DT/NT can still win with technique. 50lbs and it's probably not happening unless your technique is Rimington-like.