[Zigurd]

Life is hard for cross-platform environments. Cross-platform apps, never mind runtimes and sdks, don't have wide use. React Native is the only notable exception. While tools like Xamarin can make a living, that's mostly outside of mass market apps.

Web apps on JS are the most compelling example of an app ecosystem that has come unmoored from underlying OSs, but iOS and Android have brought back the dominance of native apps, because the underlying platforms and their capabilities are interesting and useful.

Maybe Flutter is a good UI stack for Fuchsia, and maybe easy Web app compatibility would be a boost to both Flutter and Fuchsia, but it will be tough sledding to get Flutter apps accepted by Android and iOS users. Flutter needs to find a place where it is essential, not a compromise for developers searching for a panacea.

The reason Java is the most widely used language is that Android turned Java into a platform-specific, UI-stack-specific app language.

The irony is that, because of the mountain of highly capable modern mobile apps, I'd bet that the Android runtime on ChromeOS quickly becomes the most widely used cross-platform runtime, in terms of the number of apps actually used by people and running on multiple platforms.