I've tried to find a original answer that they could give, but greed is all I can come up with. It's a shame really, because their product is not that bad. But the way they're handling it's crap wrapped in gold. They even removed stuff that were in 2.0 (days before TTK release) and those stuffs just added to the experience. (Different strike playslist, different difficulty for story mission.) They're an horizontal progression game that should keeps all of it's low amount of content relevant, but are deep in denial and increase playtime with bottlenecks.