Your ignorance of the number of players who want to replay a game in a different way is irrelevant.

You can select different main characters, create a custom character, have a party with different combinations of characters, take different approaches to different events, have things go differently, combat doesn't play out the same way, do events you were locked out of before, do events you completely missed the first time... BUT NOPE NO REPLAYABILITY HERE WHATSOEVER, NOPE!

Oh, please.