So the entire point of the Fellowship was to take The One Ring back to
Mount Doom, the only place where it could be destroyed.
My question is this: Why couldn't Sauron just, you know, sit around inside
Mount Doom? Why park yourself in a tower 100 miles away? If he'd waited around at the entrance to
Mount Doom there'd have been no way for anybody to ever destroy it.
Thus, Lord of the Rings has been ruined!