> How about 1) Write book. 2) Spend a day or two getting it on Amazon, Apple, B&N online. 3) Keep 100%.
Might be harder for authors who need marketing but I have no idea why established authors aren't self-publishing en masse.
The issue there is that if no one knows about you or your book, 100% of nothing is still nothing. Publishers also often provide advances, which can be make a big difference.
Note that I am not defending some of their questionable business practices, but to pretend they provide zero value is silly.