One gets the feeling, after listening and reading about music in the 20th century, that there were only two important seeds that started the whole thing: Stravinsky and Schoenberg. But buried beneath the the roar of the Rite and the hallucinatory and demential Pierrot was Debussy's flux of light, which passed unnoticed among the racket caused by his contemporaries' music. I'm not bashing the other's music, I'm just acknowledging the whisper among the talking crowd.
The music we know from the last century would be unthinkable without Debussy. He continued and greatly expanded what Schubert and Chopin did before, while starting what artists like Varèse and Messiaen continued after him. Then the list continues to grow: Xenakis, Scelsi, Feldman, Grisey, Estrada, even Cage. The so-called emancipation of sound, wrongly credited to Schoenberg, was Debussy's gift.
Of course I'm oversimplifying this part of musical history. For instance, Varèse, like Messiaen, not only continues what Debussy sets out, but also what Stravinsky does rhythmically. Also, while we can find a link from Schubert to Estrada, going of course through Debussy and Xenakis, Estrada goes further back to Mozart, integrating the two most powerful aspects of music, timbre and movement, seldom unified so strongly. Another such case is (can you guess?) Debussy.
On a different level, or should I say niche (just being cynical), Pink Floyd, The Beatles, and Radiohead, among many others, should also be thanking him.
Why am I circling so much around good ol' Claude lately? Well, we're analyzing a piece of his in one of my classes. Can't help thinking about all this.
By the way, isn't it funny to think there's a link between Chopin and Xenakis?