John Scalzi made an interesting point about the Kindle Unlimited subscription model.
With KU, ebook sales are a zero sum game for authors - one author's success means less money for other authors, since authors aren't paid a fixed sum per read, but a proportion of a fixed monthly pot of money.
This sort-of makes sense, since Amazon has a fixed amount (per subscriber) coming in to pay authors with from the KU subscriptions. But is it a good deal for authors?