I think this is a great summary and resource. No, it's not all you need to learn to sing, but it wasn't intended to be. Regarding singing on pitch and in tune, that too is a learned skill. A good coach or singing class will work on ear training. Sometimes the (wrong) mechanics of your vocal technique can make it difficult to hit a pitch accurately, but you can definitely improve your ability to hear a pitch and sing it. These are things that even pro singers train and receive coaching on.