For the languages it boils down to availability of relevant ecosystem and developers in my experience. Why react-native, well, because it means you have access

For the languages it boils down to availability of relevant ecosystem and developers in my experience. Why react-native, well, because it means you have access to one of the largest ecosystems and an awesome tooling catalogue. The same applies for JS as the language of choice for App (UIs). Kotlin was also a great candidate since it could leverage the already mature Java ecosystem for android. Flutters success is an outlier here that I would guess is due to Google backing. The resources and docs are good and you could rely on financial and developer backing. The decision to go with Dart was most likely to make themselves not dependent on another party for a core utility and to have a steering position on the overall projects course. If, for example, Microsoft would back a good C# cross-platform framework I would bet on it at least seeing moderate adoption. Edit: As another commenter pointed out, GO has a cross-platform GUI Framework option - Fyne [https://github.com/fyne-io/fyne https://github.com/fyne-io/fyne]