that's where you're entirely wrong.
you can't run before you learn how to walk. simples are the basics of graffiti, or anything else really.
you can actually tell, when looking at pieces or wildstyles, that the person who did that understands letter structure, cause what gives that shape of the style are usually extensions of the letter, but you learn later in time.
BATES is probably one of the best examples:
SIMPLE:
PIECE:
you can see he still keeps his letter structure, even in the piece.
all the extensions and the tilt of the letters are what gives it its shape.
hope it helped, and if anyone can back me up... please do.