So that now, after vaulting half the game, they can artificially make up for lack of content instead of trying to put effort into previous seasons of gear. Sunsetting and vaulting were the dumbest ideas to come out this far into the game. They're vaulting to extend the life of their game by making you come back later, to replay the old content, so that the gear that was previously useless can now be reclaimed. What they should have done is implemented an activity that is accessible by quest after the beyond light campaign that can be found in the glassway. The activity takes you beyond a vex portal where a planet, that has been "vaulted", rotates weekly as a vex simulation as well as a second portal for a random "raid sim". This way we can still get all the armor, weapons, exotics and catalysts we are missing. This would also give them time to rework the gear for use in destiny's current state, but clearly thats too much work. They could even have a special nightfall-like strike that has a chance of dropping a material that can be used to upgrade your sunset favorites to current specs and roll random new perks.