I agree that "... the one who endures to the end will be saved." (Matt. 24:13, ESV) But, to argue over whether the person who does not endure was ever saved is purely academic. It might make sense from the human standpoint, but to God the argument is ridiculous. The reality is the same. The rest is hypothetical. God is all-knowing. Everything is reality. Nothing hypothetical. The hypothetical is empty logic to God. The hypothetical is of use only to us with incomplete knowledge.