The statement below is false.
The statement above is correct.
More simply, finishing games doesn't matter. Any single game or fraction of a game is just a blip. The journey is bigger than that.
Yes and no. I'd rather not start a game where I know we'll have to stop midway through, particularly if it has the complexity of an 18xx, and particularly with new-to-me games. I'd like to know whether my long-term strategy has any merit, otherwise I can't learn anything from the play.