In science and mathematics building on the work of others to obtain deeper discoveries and more powerful explanations is essential to progress in these fields. But even if your results reach much deeper and wider than those of your older colleagues, this in no way negates the value of the latter's contributions to the discipline.
In music, on the other hand, things can be strikingly different. If someone takes the formal, stylistic, thematic, and harmonic elements of your compositions and uses them to create deeper, richer, and more powerful music, chances are good that he will get all the credit from posterity, while you will end up being royally fucked. Your music will be all but unknown to future generations of music lovers because it will be ignored by performers, dismissed by composition teachers, overlooked by record companies, and denigrated (if mentioned at all) by popular accounts of the history of music.
