See https://x.com/BrendanEich/status/1260733952160985089. Google, especially with the antitrust trouble they are in, is not going to try for an "ActiveX redux" act here. They definitively renounced trying to ram Dart into the Web standards here:

https://web.archive.org/web/20150328124454/https://news.dart... (yes, they took it down so Wayback to the rescue)

The GC barrier overhead is too damn high!