1. Because its content that isn't being played by the overwhelming majority of people. 2. Even though its getting such poor engagement, it still costs money and man-hours to maintain, and to make sure it works properly 3. In a game with Sunsetting, none of those activities will drop any loot that is relevant any more. 4. The point of a new game like this is to get you to play the NEW content and chase the NEW loot. Not to have you constantly circling back and playing 2-and-3 year old stuff. 5. Vaulting them will help the game run MUCH better on console. The experience of playing this game right on on console is a poor with load times getting absolutely ridiculous unless you own an SSD.