I'd love to see the numbers for "average" authors. Somehow I suspect, that there are very few non-fiction books that make actual money based on the amount of work that goes into them compared with a regular hourly rate for a subject-expert.
Based on $50/h, a book with 100 pages and 2h/page(research, structure, writing, etc) we are at $10.000 just to break even - without considering any external fees/time invested in editing, layout, design - or promotion.
Even based on a 100% earings rate, it seems save to assume that most "profitable" books are just a tool for personal promotion/expert positioning.
And/or personal fulfillment? Maybe not everyone likes the consulting or employed work that would earn the hourly rate. Plus it isn't scalable. Granted, the chance of the book breaking even may be slim, but it affords one to dream and to do what one enjoys.
Based on $50/h, a book with 100 pages and 2h/page(research, structure, writing, etc) we are at $10.000 just to break even - without considering any external fees/time invested in editing, layout, design - or promotion.
Even based on a 100% earings rate, it seems save to assume that most "profitable" books are just a tool for personal promotion/expert positioning.