Music notation and theory have become a little 'bypassed' in the modern music-making world. With the advent of DAW multi-track audio and MIDI recording – where capturing a performance and correcting mistakes is just a mouse-click away – scoring music onto paper so that someone else can play it has become a bit of a dying art.
And if you're in a hurry to make music, grabbing the gear and experimenting is so much more fun that wading through a complex textbook of opaque hieroglyphics…