OK, we disagree about how the MVP should work. He's providing value by giving his team a better chance to make the playoffs. Just because they happen not to make the playoffs doesn't mean he didn't improve their chances. That's value. As for Cespedes, he's not playing as well as Manny was, and Manny didn't win. He's not providing the most value to his team. He's not the spark anymore than Duda or Wright or anyone else. He's playing a part, and it's helping the team, but that doesn't make him the most valuable player.
As for Pujols, you seem to be forgetting that Harper's season isn't over yet. Harper's on pace to beat Pujols's highest fWAR total, and that's with UZR liking his defense a lot less than DRS. Harper's wRC+ is 20

higher than anything Pujols ever posted. Harper's stats are marginally better, and you've said yourself that the Cardinals won more because of other players. If you really think that makes Pujols the better player, you clearly don't understand, like, the most basic principles of logic.
As for Arenado, again, he's just not one of the best players. He's good, for sure, but he's a 5 WAR player, not a 7-8 WAR player.