I don't know any popular app (Facebook, Spotify, Deezer, Play Music, Gmail, Pocket, ...) that uses such an hybrid framework. All the major apps have teams ded

I don't know any popular app (Facebook, Spotify, Deezer, Play Music, Gmail, Pocket, ...) that uses such an hybrid framework. All the major apps have teams dedicated to each platform. They might share some code with a shared c++ library or J2objc (or a similar solution) but never a write-once ship everywhere app. So that would only allow them to gain the low popularity/quality app. That's not really a win.