If we’re being honest, there is no logical or reasonable explanation for sunsetting in destiny. At the end of the day it’s nothing more than a big -blam!- you for playing the game. They really want this game to be a big mmo like WoW or something but refuse to accept the fact that Destiny can’t and never will be, Destiny attracts a drastically different audience, that audience will never be happy with you taking away or outright making what they earned and loved useless in most activities. Sunsetting is like increasing the level cap in borderlands but not allowing you to farm old legendarys at the new cap.