The code just isn’t the main effort of work anymore. Anyone can generate the implementation, so it makes more sense than ever to instead hammer out the what, why, and how that underlies any code change.
I see all projects moving this direction. Makes more sense to hash out a plan together.
Code was never the main effort of work, but it was a clear signal that someone has done the main effort, which is understanding the codebase, designing a new feature, or investigating a bug, and have the knowledge to write the code. By the time you get to review, you can expect a knowledgeable person on the other end.
It’s the same about published journal article. A lot of them are a few pages. That is mostly one hour of typing. But everyone knows that typing it is not the work.