Yes. And normally if you open a PR, a maintainer will come accept it and update a version. If they are “slow” (undefined), then we normally start to ask if we can move it to SciML/JuliaArrays/JuliaLinearAlgebra/etc. so we can get other people access to help with the maintenance.
In very drastic circumstances, say a maintainer hasn’t responded to any message for like 6 months, we have had some situations where a repo is forked, the URL is updated in the General registry, and then a new maintainer takes it on. We of course only do this in the most drastic of cases because it’s better to just have the original maintainer give their graces. I only know of one scenario where this was done. It was because nobody ever heard from the maintainer again and no one had admin access to the repo, so to keep the project alive the fork was turned into the successor. In all other cases, people were happy to say “yeah I got a new job and I haven’t had the time to maintain, I’d be happy to pass on the admin to xyz” and then the process continued.