In my experience, writing (or any other art) is maybe the most downwardly-mobile profession there is. The supply of artists far outstrips the demand for art, and getting your first job often depends on proximity to industry gatekeepers. I can't speak specifically for the publishing industry, but in film and television people tend to get writing jobs through personal connections.

The four paths I've seen for people who make it in film/tv:

* Have a family member who gets you your first job.

* Have rich parents who completely subsidize your work for a few years and provide anonymous funding for your first feature film.

* Have upper-middle class parents who partially subsidize your work for a few years, and get ready to be an assistant for 3-25 years while you build connections with the business bros that determine your future.

* Have lower-middle class parents. Be extraordinarily driven and ignore all material needs while you win festivals and get noticed.

The lower you are on the list, the more effort it takes to maximize your probability of success. Realistically, almost no one makes it from the bottom category.