Anyone can make poor man's stew (add one cup of everything edible in your cabinet, season to taste) but pretty soon, you've mixed too many flavors and the stew becomes a brownish gloppy mess that doesn't taste like anything recognizable, let alone edible. Sure, its nourishing and it probably won't kill you, but adding chocolate sauce, mushroom soup, sour cream, curry, wasabi, cayenne pepper, blackberry jam, and fruit cocktail together makes a meal less than the sum of its parts.
D&D's mythos are getting like that.