It's very interesting to read why Cornelius Cardew became disenchanted with academic avant-garde music. He wanted to reach as many people as possible and change their consciousness. He wanted to reach the "working classes" in England. The kind of music he was making was very much from the academy, even though it had a lot in common with things like free jazz and improvisation, and he felt that it was the music of the elite, and that he wasn't really speaking to the people.
You have filled my tea with lumps of sugar, and though I asked most distinctly for bread and butter, you have given me cake. I am known for the gentleness of my disposition, and the extraordinary sweetness of my nature, but I warn you, Miss Cardew, you may go too far.