Edit: Misleading charts, figures and conclusions ahead, see @nathancahill's reply
https://npm-stat.com/charts.html?package=babel&package=types...
Babel has faltered since the V6 release, TypeScript is still growing fast, so I'd expect the React world to follow suite, even if Facebook itself pushes Flow...
NPM downloads in August (rounded):
typescript: 2,000,000
babel: 620,000 (down from 890,000 in November 2015)
flow-bin: 120,000