I have to agree. Google suffers from a really bad case of ADHD when it comes to creating anything for consumption by outside developers...there is a long list and Dart and GWT are just two that stand out because there are large codebases out there that suffered because of these decisions.
Frankly, I'm surprised that Go has made it this far - I mean, it's a great language, I get it, but Google is fickle when it comes to things like this.
Dart's relevancy is heavily dependent on Flutter's success.
Seeing how Chrome team pushes for PWAs, Android team woke up and is now delivering JetPack Composer, and we still don't know what is going to happen with Fuchsia, the question remains.
Frankly, I'm surprised that Go has made it this far - I mean, it's a great language, I get it, but Google is fickle when it comes to things like this.