Maybe because only engineers have the luxury of providing a service that can't be duplicated? I have trouble imagining viable SaaS equivalents for media. What would a, say, Books-as-a-Service look like?
You can get 1 free Kindle download a month with Amazon prime. However, I think Porn is leading the way on that one. There are plenty of sites that give you access to a growing collection of stories for a monthly price, and one that allows free access to it's collection but charges for a better search and bookmarking system.
Which I guess boils down to either the patronage system, where you can sponsors people to write (ex: epic poetry) or the organizational system where you can distribute free content and then give kickback to the most popular authors like many blogging systems do.
PS: Batoto.com is an odd mix as it returns money to people who translate works but not the original authors. Sort of like a pirates auction house. The advantage for users being a nice interface and rapid updates.
I'm being very radical here, but the thought of the only books being published being by people who actually want to be read rather than waant to be rich is not a problem for me. For craftsmen whose primary goal isn't to communicate or entertain, I'd suggest patrons. I'd certainly sponsor about 1/50 of a writer spread across a curated pool. I'd probably sponsor about 1/200 of a curator. They wouldn't have to even send me the books, I'd just buy them from the printer with the best quality to cost ratio.