You do what you do and if it earns money that’s nice but most often it does not and it is better to do your earning doing something quite different so that you never need an audience. An audience is always warming but it must never be necessary to your work. Being necessary is what makes craftsmen and fashion and commercial art. There is nothing wrong with these things only they are not art and it is funny how everyone always mixes them all up and doesn’t want to know the difference between art and the rest. That is why mostly the creative artist never earns much from his art because nobody wants to know the difference. (Gertrude Stein, in How to Write)
Stein, Gertrude. 1975 (1931). How to write. New York: Dover Publications Inc. [This Dover Edition, first published in 1975, is an unabridged and unaltered republication of the work originally published by Plain Edition, Paris, in 1931, in an edition limited to 1000 copies.]
Google Books has a useful facsimile/sample of How to Write.