Making MLS Cup is not the prize. It is not the climax of a journey. Merely making the Final is still a failure. The Seattle Sounders are not finished yet. There’s another game, a full 90 minutes for them to write an unbelievable script.
Imagine the Princess Bride but Inigo merely avenges his father while the Man in Black never rescues Buttercup. That movie is a lot less interesting. It is no longer a story of true love, success and fantasy. It is just a vengeance tale. It would feel unfinished.
Think about Star Wars: The Force Awakens.