So here’s an interesting attempt at creating the books of the future: https://bubbl.in/
Here’s an example of what’s possible so far: The Solar System by Marvin Danig
It’s tough to beat a free price tag. So competition will likely struggle against this one, especially since authors won’t necessarily have to market their books as the site itself is a sort of storefront.
It’s certainly innovative and has a lot of factors already accounted for to yield interest. There’s also a fair bit of good response from the hackernews community too: https://news.ycombinator.com/item?id=9861740
We’ll see how it goes from here.