They had the wrong idea about how to implement endgame anyways.

How they implemented it: Cap the game at level 60, then added an additional difficulty mode (inferno) and made it extremely challenging. In doing this, they hope that players will take months to clear inferno
How it went: Hardcore and very seasoned players cleared it within weeks, and a few have quit the game due to the lack of things to do in the game. This is no surprise, as the items you can farm in game are max ilvl63, lack of variation in item stats, drops. Majority of players (casuals) felt that inferno was incredibly frustrating, some have quit because of this and this number continues to rise every day