I can imagine someone, who is in no great hurry, needing the psychological crutch of paying someone for a year of three to be 'mentored' about writing. The logic would be: "you pay a guy to tell you what to eat and how to exercise, you pay a guy to teach you a musical instrument, you pay a guy to tell you how to speak and dress, you pay a guy to teach you to write." Of course, for this to work out that way, the teacher really must know enough to fulfill the role of a good crutch.
In a sense, for some people 'learning to write' really is like learning to ride a horse, or to arrange cutlery correctly, or to play the piano--a skill which helps add polish to one's class position, not necessarily a skill which is an entry to a profession, or even an enthusiastic hobby. They don't become actual pianists or jockeys or wedding planners, just people who can do those things should the situation call for it. So, to repeat myself, I can imagine some sort of upmarket service that provides a mentor to turn one into a functional writer. It's just that I've never seen such a service yet, just downmarket bottom-feeders.