I think this is a bit too much of an absolutist take. One that turns too many people off from reading, and can add an unnecessary air of elitism around it. If you pay $14.99 for a book, you aren't seeing returns only after ten hours of dedicated reading. Even reading one chapter can yield returns that are equivalent to $14.99, if it's a good book. With non-fiction, you can also pick chapters that strike you as the most interesting and start directly from those, getting faster 'returns on investment'. Then going back and reading the whole thing if you're sucked in.
It's very common for sites to publish curated segments of books, whether were talking science related things or not. And even getting double the amount of that text by purchasing the book (compared to the short excerpt) can be worth the price of admission.