You seem to be conflating competitive games with using game mechanics to achieve a result. Gamification goes well beyond points, badges and leaderboards and helps managers tap into intrinsic motivators (like personal satisfaction) to achieve results. Done poorly, its all PBL all day and doesn't work for the reasons you've outlined. I think its fair to say that "bad gamification" doesn't work, but its a big leap to toss out the entire field based on the narrow selection of "bad execution" that you use in your example.