https://trends.google.com/trends/explore?date=today%205-y&ge...
or how about
https://trends.google.com/trends/explore?date=today%205-y&ge...
Maybe alexa matters?
https://www.alexa.com/siteinfo/vuejs.org
https://www.alexa.com/siteinfo/reactjs.org
Or maybe one community uses their respective primary domain more than the other for one reason or another.
React also has more than 4x as many dependent packages in npm, which could be propping up its install count.