hmm, you havent defined what your take on 3-4 months actually is yet, in most hardcore games, it takes a long time to get to the start point of end game so to speak (i.e enough raid worthy gear), and its designed to, as opposed to just getting full BIS in that time, getting just to the point you NEED to clear and progress in the content is always has variation, but wont take 3-4 months to reach that.
CLEARING the content and getting full BIS is another matter, you dont NEED to be in full BIS to do current content, this is just peoples greed talking.