When it becomes a service where you make money but the source doesn’t is it still fair use?

Yeah. No one is out there suing the shit out of cliff notes because they published a summary of Catcher in the Rye.

they might if cliff notes starting copy pasting parts of the source into their articles and passing it off as original writing though :)

Newspapers generally don't "pass off" quotes as their own writing. They make clear which parts they quoted.

The Tolkien estate should get busy suing all the fantasy writers, comic artists, game developers and board and card game companies. Lots of cash there.

They have done some of that actually. Tolkien will be public domain in the nations that are at aithors death+50 in a few days. Sadly, it will be a much longer wait in mine and many others.