The stars have fallen to the classic problem of becoming a goal and stopping being a good metric. This can apply to your measure just as well: issues can also be gamed to be opened, closed and responded to quickly, especially now with LLMs.
I especially love issues automatically "closed due to inactivity" just to keep the number of issues down :V
"When a measure becomes a target, it ceases to be a good measure"
Was it ever a good metric? A star from another account costs nothing and conveys nothing about the sincerity, knowledge, importance or cultural weight of the star giver. As a signal it's as weak as 'hitting that like button'.
If the number of stars are in the thousands, tens of thousands, or hundreds of thousands, that might correlate with a serious project. But that should be visible by real, costly activity such as issues, PRs, discussion and activity.