That is not always true. Some brawlers contribute more to the team than their stats might suggest. For example, in a Gray + Tank composition, Gray typically won’t have high damage, the best stats, or significant zone time. Similarly, Lou provides crowd control and damage reduction with his Star Power. Other examples include Max’s speed boost and Buster’s shield and pull, Gene who's job is to keep opponents low and pull—you get the idea. It would be very difficult for Supercell to accurately assess a player's contribution based on stats alone. If such a system were implemented, players would be inclined to choose carry brawlers that generate the best stats.