Always keep this in mind that gear never lasts, even exotics may not last. If you play WoW you know that all gear including legendary (exotics in WoW) only last until you hit the next max level, which is 40 in this case. Only things that never goes out of style are cosmetic items such as cloaks, marks, shaders and ships. But in reality there is no incentive to farm these because they are always there (except for faction vendor stuff since they get updated with new stuff). Running stuff now would have only been worth while if they said "x item will no longer drop in x raid when TTK is released". I do find it kinda dirty on Bungies behalf though that they remain silent on this when we're a month away from TTK. Only reason they do this is because their is nothing that keeps us addicted to the game besides loot. That's why they need to add more cosmetics to the game aside from faction stuff to keep us hooked. TL;DR: Gear and legendaries (exotics) always become useless. Bungie should give heads up if they're doing this at least 3 months in advance. Also need to add more vanity/cosmetic stuff aside from loot hunting.