We do not have a monorepo, and you can practically watch the gears turn when we mention any process change that involves changing the CI scripts. And this part may be projection, but I am nearly certain I see people subconsciously avoiding solutions that involve systemic CI changes.
I got tired of making clerical errors or helping others fix theirs and went through and moved a bunch of configuration out of our CI configs into source control. So for my projects making changes is easier, but I still bump into mature projects that still have the old patterns because nobody even wanted to edit the configs one last time.