I have just read First Person, Richard Flanagan's new novel about a hungry young novelist struggling with ghostwriting the life of an impossible con-man for a demanding publisher. It captures exactly the sort of despair we have all faced at times when trying to make a living in the creative world.
I think perhaps texts such as this should be recommended reading on any vocational creative writing course and in every art school, (and every drama school come to that), in order to test the mettle of the would-be creatives.
I remember as a teenager reading Keep the Aspidistra Flying by George Orwell and Of Human Bondage by Somerset Maugham and being both excited and appalled. Excited by the prospect of escaping an ordinary life in order to be a great poet/artist like the heroes of these books, and simultaneously appalled by the poverty and rejection that they have to face as a result of their choices.
If you can read books like these and still want to be a professional creative then the chances are that nothing will ever stop you having a go.