The temptation to offer different / inferior / limited content to scrapers will be too strong, so such solutions are doomed to fail.

This would likely work as "Cloudflare SideChannel", a (hypothetical) Cloudflare product that would let scrapers download the pages that humans actually visit, as they are added to the CF cache. It wouldn't work for the non-Cloudflare part of the internet where humans connect directly to the servers that have their content.