The real argument shouldn't be about protocols becoming obsolete, but programming languages that are "less efficient" could eventually become obsolete in favor of highly scalable and performant languages due to LLMs when the main gap becomes knowing how the tech works at a high level, and not the syntax, why code in one language over another if you don't need to worry about messing up on syntax, only about reviewing logic for sanity and correctness against business rules as well as validating that it is stable code.

Anybody who thinks that you can just chuck unstructured data into LLM and YOLO the app is an idiot.

This works up to a point, and then it doesn't. And you're left with tons of inconsistently formatted data.

My company is built on protobufs from ground up :) We use it in the database, for remote calls, on the frontend, etc. The protobuf language is not great, but it's about the right balance between too expressive and too restricting.

And the best thing is that it's compact, compared to OpenAPI.

I feel exactly that way about REST. The assumption that LLMs make schemas obsolete misses how structured outputs actually work in production. When you have probabilistic models generating code, strict contracts become more critical, not less. It is no coincidence that several major LLM platforms rely on ConnectRPC and Protobuf for their own APIs.