It's another way Bungie invented for make people grind endlessly but if they know that in a year they will lose most of what they worked so hard for... why bother at all? I was trying to get some legendary weapons from year one and know I just don't see absolutely any reason to do it. I don't think every weapon should be upgradeable after TTK but at least give the choice to players to choose like 3 or 4 weapons from year one to keep and upgrade with the next expansion. That's what gives the feeling of continuity to the game. At least it's my opinion