Wasps do pollination too.
it also happens that they sting stuff repeatedly, kill stuff many times their size over, set up shop anywhere they want with the only responses being specialized gasses or extreme(ly stupid) methods of getting rid of them and generally make things unpleasant, they also make no honey.
its not that wasps do nothing, it's just that the one thing they DO is oft outweighed by the other things they also happen to do.