The purpose for much authorship is to sell copies. Writing a novel is a bunch of work, if that work doesn’t sell, the unpaid bills tend to cause problems. Tuning to sell more absolutely makes sense.

Novelists frequently have editors and other people who comment on and refine drafts. I don’t know what the OP is really asking- of course authors get opinions and feedback on drafts. If they want it. But for a classic buy-the-novel-read-the-chapters, clicks won’t be clicks of engagement, or they won’t matter because you pay before you read, so A/B testing won’t help. I’ll pay based on a review, and if the version I read is not the one I heard was good, I’ll be disappointed in the author and whatever medium provided me info about the work.

Possibly the OP is thinking of a new literary form.