This is a very speculative question. Suppose somewhere in the universe there's a civilization that's invented the [insert favourite musical instrument here], but only have one hand. They can write songs of course, but they won't have music as rich as we do, because we can play the [instrument] with two hands. The set of all music that can be played with two hands is trivially bigger than the set of all music that can be played with one hand.
But this can go on. The set of all music that can be played with three hands is trivially bigger than the set of all music that can be played with two, and the set with four hands would be bigger than the set with three, etc. Therefore, could it be that there are beautiful pieces of music today's composers would love to compose, but are unable to, because they're thinking only in terms of 2 hands?
Edit: Thanks for the answers. To clarify, I was thinking that one of the rules of solving puzzles is to consider the question "am I making any assumptions that aren't in the problem?", which in this context would be "am I not able to compose a more beautiful piece of music because I'm assuming the player only has two hands?".