In LLM-friendly repositories it saves everyone's time if the maintainers are the ones steering the machines, and in LLM-unfriendly ones it saves everyone's time by not having generated PRs thrown at the maintainers.
No, I don't think that is true. Anyone who used LLMs in greater degree (e.g. at work) knows for a fact that the output and therefore the end result work heavily depends on the human involved, and their thought process. Of course for anything that isn't completely trivial.
That's what issue trackers are meant to capture.
I could see maintainers wanting to take sole control over the code, and rather than swatting down PRs they can just guide AI to fix reported issues themselves, and merge what they approve of. Cut out the middle men.
The problem is that the last part changed drastically with LLMs. You can get a lot of solutions easily by prompting an LLM. But that also means you don't need outside PRs for that anymore, and just prompt the LLM yourself.
That means two things in my opinion:
1) People haven't internalized that yet. For a lot of people, a functioning solution to a problem with often quite a bit of source code is equivalent to "adding value" - because in the past it was. It meant you thought about the problem, understood it and found a solution. But it was that thinking that added the value.
2) The minimum threshold for adding this "quality" rises quite a bit. A lot of problems can now be solved very fast with an LLM by someone who understands the code base well enough. You don't need a PR for that.
I suspect, that means in the future you could both get and need less contributions to OSS projects in general.
We'll see