"Why Not return to an Instantaneous Possession in the Endzone Rule?"
Because then all a patriot receiver would have to do is reach out and touch the ball while it flies through the end zone and they'd call it a possesion and a TD
I say that jokingly but in all seriousness the refs will use WHATEVER rule to favor who they want to. I remember thinking the very thing about some of those 'catches' Jerry Rice used to make. He would literally stretch out on the side line and seemingly just touch the ball while his feet were in bounds and they'd call it a catch.