Why does everyone put 3D Mario, Zelda, and Metroid in the big seller category for Nintendo?
Nintendo has more than a few series bigger than Zelda. Many of them are from Mario but it still counts. As for Metroid? ...I wouldn't even rank it in Nintendo's Top 10 from a sales perspective. Sure, it gets great reviews but from a business perspective, it's odd that Nintendo puts multiple Metroid games out a gen. (Recently)