comparing great coders of the past to great musicians is a little bit wrong...
Great musical works by geniuses of their day were exposed, meaning, if you were appropriately skilled, you could simply write them down and look at the score, the code, and see directly what the Genius had wrought. With programming it is more obscure, unless the code has been released to the public, all you have are errors, mistakes, and interface design to illuminate you as to the processes and logic that went into its creation.
one example would be google. you don't learn alot about the google backend from its web interface, but you know there is some serious stuff going on in the background to spit out a result to you based on the words that you typed in cross referenced with what amounts to basically all of human knowledge.