Look at the top of the standings and you find the better teams. Look at the top of the leaderboards and you find simple explanations for why the better teams have been successful.
The Boston Red Sox have been successful in part because Mookie Betts and J.D. Martinez rank first and third in baseball in wRC+. The New York Yankees have been successful in part because they lead the majors in home runs. The Houston Astros have been successful in part because their pitching staff leads the majors in strikeouts.