I agree that D&D is not the best game for every genre or setting. Sure, you technically could adjust the rules for D&D to fit any style of setting or genre.
However I do not always think that is as easy as it seems, or as some people say. (Your mileage may vary, this is my opinion.) There are lots of other great games out there, and I think playing lots of different systems might introduce you to a game you like better, or at the very least improve your ability as a GM by absorbing different practices from different games.
Unfortunately this isn't an option for everyone. Either they can't afford to drop money on a whole new set of books, or their players aren't willing to experiment. In that case, you do the best with what you have.
However I do not always think that is as easy as it seems, or as some people say. (Your mileage may vary, this is my opinion.) There are lots of other great games out there, and I think playing lots of different systems might introduce you to a game you like better, or at the very least improve your ability as a GM by absorbing different practices from different games.
Unfortunately this isn't an option for everyone. Either they can't afford to drop money on a whole new set of books, or their players aren't willing to experiment. In that case, you do the best with what you have.