Rank is a weird value to plot things against, ratings make more sense. Then we can calculate how many dollars per magic fun point out of 10 you can spend, although the Bang for Buck chart goes over that.
The Bang for Buck chart always seemed weird to me. I think it's because the lowest games ever really go is somewhere in the 6s and the highest a game goes is into the 8s. Close Encounters of the Third Kind and Mr & Mrs. Pac-Man aren't games you ever hear about being great value games, but they're high on the bang for buck charts. Their low price reflects the quality of the game.