Dart/Flutter was never a technical issue, but a political/monopolistic issue. The underlying monopoly has not changed, so I don't really see a path forward unless the chromium team magically changes leadership.
I guess my point is, if the big Chromium team couldn't pull something like this off, who else would? At this point major web updates tend to get born in one of the big tech companies funding web development, either directly or indirectly (Mozilla being funded by Google)
I personally don't think dart/flutter was good enough of a solution to be worth everyone's time. When this actually happens it will be more of a paradigm shift than that.
That's why (which I said in the other comment) what needs to happen is that innovating in this space needs to become a lot easier.
