We'll see what happens.
I'm not sure that the economics of Kindle Unlimited could ever really work--either for Amazon or for writers and publishers.
The old Kindle Unlimited compensation plan encouraged authors to game the system by publishing short books at a high frequency.
The new scheme--payment by page read--attempts to mimic the payment plans of music subscription services like Spotify. I believe that Netflix uses a similar plan to compensate film distributors.
I have my doubts about the sustainability of Spotify, as I've written here before. And Netflix encourages the bulk production of bad movies.
But where books are concerned, there is yet another issue at play: It remains to be demonstrated that this is something consumers even want.
We consume music and movies in "binges". You might listen to a dozen songs while you're on your exercise bike. And even a low-volume television watcher like me can easily watch two or three movies or Walking Dead episodes over the course of a snowy afternoon.
By contrast, a "high-volume reader" is someone who reads maybe a book (or perhaps two) per week. No one consumes as many novels as they do songs, movies, or television series episodes.
This is simply a matter of the time involved in each activity. It takes about three to five minutes to listen to the average song, and no more than two hours to watch all but the longest movies.
On the other hand, you might spend twenty hours reading a 400-page novel, usually broken up over many days.
I understand the objective behind the Kindle Unlimited prescription model. But beyond the disruption it poses for writers and publishers, is this something that readers really benefit from having available--to the tune of $9.99 per month?