This issue with READMEs in particular has driven me nuts for the decade I've been doing ROS related robotics stuff. So many repos where the only surface clue (i.e. before diving into the code) of what it does is your interpretation of its name.

But I'm pretty sure it's universal, like you allude to. And not just open-source; but at work, too. I feel like I'm the only one in my company that makes PRs to edit the READMEs to explain what a repo is for, and what repos it might relate to. (I was much happier in the past when we had a couple mono-repos; now the trend is every little project gets its own undocumented repo, alas.)