One thing that was pretty clear was that our audiobooks were at the mercy of publishing houses / content owners, and a lot of restrictions came from licensing deals (geographic reastrictions, time-based, formats, etc), so I'm inclined to assume that the low cut for authors may be due to publishers wanting a big cut of the sales.
That said, there was a floor which we were not allowed on, and I believe that was the sales floor, so there could have been a whole other side to this company that I was not exposed to.