It wasn't one of those catches (or catch opportunities if you prefer) in which the player comes down on just his hip, his thigh, elbow or backside. He landed with control of the ball in two hands, managed to cradle it as he was striding, planted for a third step and dove to the end zone. If you choose not to see it that way and apply the rule as it is written, that's fine. But the whole premise of possession is screwed up because of this "continuation" bullshit. No one complains when a guy manages to press a portion of the ball against his shoulder pad with one hand as he tip-toes the sideline and then runs out of bounds, even though his only "football move" was to simply catch it for a split second with two feet down.
You could make the argument that Dez controlled the ball (even if it's just for a half second) with two feet on the ground before he dove for the EZ. If you look at it that way, then the ground can't cause a fumble and it's Cowboys' ball at the 1/2 yard line.