By your own admission, from a story perspective, there couldn’t be a story if they followed your strict interpretation of the title’s meaning, which is why they wouldn’t. I’m sure that back then, the title was meant to sound cool and edgy, and the fact that you CAN kill your opponent does support the name to an extent. But nowhere in any aspect of the story does the game state that one opponent HAS to kill the other, regardless of the title.
Honestly though, they could’ve called it “Death Duel” and openly stipulated in the rules of the story’s tournament that two characters enter, one leaves, it still doesn’t mean that every battle has to end up with someone dead from a canonical story perspective. The narrative dictates that the title does not govern it because it obviously can’t or else, as you said, there’d be no sequels.
Say it’s a stupid, pointless title for a game, if you want. But saying the game makes no sense because everyone doesn’t die in the first game because the title implies “fight to the death” is to me, about as logical as saying that Street Fighter doesn’t do it right because not every fight is on a street.
That’s my argument. You don’t like it, that’s fine. I’m tired of derailing this thread, so let’s just agree to disagree.