This is a great (=true) answer, but doesn't it basically argue that Copyright is a false premise? The evidence seems to be that (1) 90% of the money does not go to the author; and (2) In spite of (1) it still makes sense to do what it takes to publish. Logically, one infers that a copyright monopoly is fairly replaced by something with 10% of the social cost, provided that "springboard to getting recognition and open doors" effect is neutral. Is this lattr assumption only possible through copyright? What if there was something like an Award or &tc stamped your resume?

On Leanpub, the author gets 90% royalties minus 50 cents per copy. So, on a $10 book, the author gets $8.50 (85%) royalty, and on a $20 book, the author gets $17.50 (87.5%).

Just because publishers have historically paid 10% royalties does not mean it has to be that way in the future.

So, questions of copyright should be a debate about what is fair based on a range of arrangements. Personally, I'm in favour of 14 year copyright, not the "author's death + 70 years" madness that exists now...

It says nothing of the validity of copyright, but it says a lot about the importance of distribution and marketing.

I couldn't agree more. The effort involved means the hourly rate is fairly dismal. But right or wrong it immediately establishes you as an expert and certainly stands out on a resume.