Ideally, yes, but there's a reason they're called staples. It's very easy to have a diet where most of the _calories_ if not actual volume nor mass of food comes from grain. Grains and fats are very calorie dense, but grains are far cheaper than butter or steak. Many civilizations have been based on a huge portion of food being tortillas, rice, bread, pasta. Grains are important. Whether they should be as big a part of your diet for health reasons is another question, but their historical importance due to calorie density is not in question and is self evident.
Ideally, yes, but there's a reason they're called staples. It's very easy to have a diet where most of the _calories_ if not actual volume nor mass of food comes from grain. Grains and fats are very calorie dense, but grains are far cheaper than butter or steak. Many civilizations have been based on a huge portion of food being tortillas, rice, bread, pasta. Grains are important. Whether they should be as big a part of your diet for health reasons is another question, but their historical importance due to calorie density is not in question and is self evident.