> so all you need is for paying clients to not be motivated to redistribute the chapters in an organised way

This is exactly what copyright is.

I agree that you could work around this in a world without copyright (e.g. by watermarking content and blacklisting), but it would be difficult and make the whole profession less viable.

Mass distribution and payment becoming accessible/low overhead was an extremely helpful development for authors in my view, and removing copyright would have the opposite effect (but cutting it down even to several years would change surprisingly little).