Why not? A player can and should reasonably be able to keep and use anything they've acquired until they find something they feel is better. To this point in the game, bungie has failed to consistently provide better gear. Until they do provide better weapons and armor, we should be able to keep upgrading out current gear. I understand "better" depends on opinion, but each expansion has had similarities that have trended thorough out it. TDB had low impact high RoF ARs, HoW ha low impact highe RoF snipers and not very many good options for heavy weapons. If you use use the archetype that they give you you're in luck, if you don't you wind up ascending the previous gear. I don't like being forced to play the game the way someone else wants it to be played.