It takes far less resources to alter PvP than it does PvE. If PvP was dropped and the resources were allocated to PvE, you would probably receive the equivalent of a few more strikes. The downside is that you would see a steep drop in population. PvP is what keeps the game afloat during the "down" phases of Destiny, so dropping it entirely would not be beneficial. I do agree that weapon nerfs should be separated thought between the two.