What people like you don't seem to get is that they bring in new weapons to fit the new end game. The old endgame is still there and you can run it if you'd like. For example fate bringer will always be the best way to handle the abyss, much of poe and many other missions/events from that time. But fatebringer was never supposed to be the weapon we killed oryx with it is an outdated relic as far as this point in our guardians story is concerned. The reason you grind is not for the future it is for the present. And if you feel really upset about this answer me this when was the last time you used your lvl 99 meutoo, what was the point if you don't use it now?