Well, they consider RoI year 2. Typically they've never changed quest lines until the year changed. Just like how you could still do the Forsaken Quest for Eris even while HoW was out. Problem is... lots of the quests are all centered around many different bosses only spawned in the patrol area's, whereas, things like the Sword of Crota has his own little mission and Pack of Wolves were very generic. But, while those can be changed, it's still year 2. And that's what they seem to have stuck with. So it's not surprising they won't do away with them yet.