I guess the political wars of JavaScript vs Dart, ChromiumVM and Chrome team dropping Dart on the floor, causing the departure of the original design team, kind of helped to Dart's success.

The political wars at Google with Dart are quite visible from outside, with Fuchsia picking up Flutter, and strangely the future of Android UI looks pretty much like Flutter, after too many times asking Android team about what was their opinion on Flutter for Android development at IO Fireside, meanwhile the developers' survey has had questions about how much we cared to see it supported on Kotlin multi-platform.

So yeah, had Chrome decided to push Chromium VM no matter what, Dart would be as successful as Go by now, after all younger generations don't seem to have any problem being Chrome developers.