We will never know and no Penrith fan is going to entertain the possibility, I get that
At the end of the day Penrith had injuries in that finals series and won the GF by 2 points, I don't think it is an extreme opinion to suggest latrell makes 2+ points difference and/or could have come up with something to break the game open.
Speaking of Cleary, if Latrell played and Cleary didn't and souths won by 2 points, you would probably wonder what if wouldn't you? as I'm sure you would feel certain Cleary makes up the 2 points.