That being said, it doesn’t take a lot of effort to differentiate these cases. Google was indexing copyrighted works and providing access to limited extracts. They weren’t transforming them into new works and then selling access to those new works over APIs.
Imagine OpenAI had invented a software program that turned any written text into an animated cartoon enacting the text. That would obviously be creating a derivative work and outside fair use bounds. That they mix a bunch of works (copyrighted and otherwise) into a piece of software doesn’t allow them to escape that basic analysis.
Google showed a “clip” of the original work, no different in scope than Siskel & Ebert showing a clip of a film as they reviewed it. The uses are not comparable.