You can be free and poor or you can live in reality and live for a paycheck. No one is allowed to just do what they want. Not writers, not actors not salesman, not librarians, not teacher, no one. You always have a boss and someone telling you what guidelines you need to follow. If writing is a career, then you have to abide by the demands of the publishing world. The demands of society which is driven by bottom lines. I'm not sure what her point is, honestly. To write for a sense of freedom and to hell with marketability? That's what private journals are for. If you want to be published, eventually you'll have to do as your told to some degree. If you want to eat food and have a roof over your head, you will also have to do likewise. Art can be beautiful and meaningful when it's motivated by and inspired by emotion and not profit, of course. But it doesn't mean your art will sell, and if so, it doesn't mean anyone else will ever see your art to appreciate its beauty and meaning.
Maybe I'm completely missing her point.