Long story short: Server architecture + age along with an always-increasing load with each new activity added, fluctutating with how many players are actively on. For how awful content vaulting is, with how awful the servers are NOW, it would be far worse if we still had Year 1 content. Which has me curious that they announced "No More Vaulting". If a server overhaul is / was in the works for Lightfall, then that would win a lot of people back. It wouldn't make sense otherwise unless they're too high off their own supply and are just pushing it through while hoping the server rooms don't ignite.