Flutter is going to die unless they actually release Fuchsia and force everyone to jump ship. Dart got lucky with the AdWords team that is all about it. All the original Dart designers have left Google and are no longer related to the language.

Android team is pushing Kotlin/Native for common code across iOS/Android, came up with Jetpack Compose and rebuilt their reload code from scratch for Android Studio 3.5. When asked about Flutter they always give the "use what is best for you" kind of answer.

Go is still playing catchup with majority of internal services written in Java/C++. Although it already has some small victories in ChromeOS, Fuchsia and Android GPU debugger.

Kubernetes was originally written in Java, was rebooted into Go after another team took over and its codebase suffers from lack of generics support, leading to a pile of code generation.

Some devs dislike so much how AngularJS was so badly managed, that they still mix the Angular/Typescript variant with AngularJS.