While there is a mention of Hacker News, I was surprised to see that the authors apparently hadn't attempted to correlate popularity with Reddit links. Anything that I've had become remotely popular is because it got a few upvotes on HN or Reddit...and anecdotally, I've seen Reddit/HN launch niche libraries into the 1000+ star group, even if the library is relatively niche (hell, I'll star things that look cool and had interesting discussion, even if it's likely I'll never clone/fork the repo)
Meanwhile, libraries that were ubiquitous by the time Github became popular have relatively few stars. The most prominent example in my mind is ruby/rake, which has just 627 stars: https://github.com/ruby/rake
ruby/rake is in maintenance mode, so there really isn't a lot of reason for people to notice it or even star it. You can see how active it is, in the screenshots below:
And as the last screenshot shows, in the last year, they only changed 104 files with 227 commits from 23 contributors. And if you look at the churn graph, there wasn't a lot of churn between 2011 to 2015.
Now compare this, to something like GitLab (18,000 stars), which is my goto repo for showing high rates of activity. This is there churn for the last 7 days, which doesn't count added/deleted files and changes by merge commits. And the reason for not counting added/deleted files, is I was told they are doing a lot of restructuring.
In the last 7 days, they changed 505 files with 390 commits, from 35 different contributors. In one week, they doubled the activity of ruby/rake's one year activity. What would be interesting to know is, of the 35 contributors, how many are GitLab employees.
I would also love to analyze GitHub's and Atlassian's Bitbucket development repos. I can't imagine they are iterating at the pace that GitLab is and I have yet to find another open source project that is going at their rate.
Meanwhile, libraries that were ubiquitous by the time Github became popular have relatively few stars. The most prominent example in my mind is ruby/rake, which has just 627 stars: https://github.com/ruby/rake