Economics of conventional publishing
While waiting for publishers to read the proposal, I was reading books like Marilyn and Tom Ross's Jump Start Your Book Sales (recommended) and it began to sink in on me that, even when a publisher accepted the book, all the marketing responsibility would still rest on me.
Publisher's just don't market. They have no clue how to reach the audience for whom you wrote, what periodicals they read, what bookstores they frequent, what trade shows they attend. They have no staff to find these things out, and no budget to spend reaching your audience if they did find them. If the author doesn't do this, nobody will.
Here's what a conventional publisher does:
In exchange for these modest labors and risks, the publisher keeps 85% of the gross receipts. Such a deal!
But there's a new deal now...