GitHub has all kinds of private internal metrics that could update the system to show a much higher signal/quality score. A score that is impervious to manipulation. And extremely well correlated with actual quality and popularity and value, not noise.

Two projects could look exactly the same from visible metrics, and one is complete shell and the other a great project.

But they choose not to publish it.

And those same private signals more effectively spot the signal-rich stargazers than PageRank.