Contrast Dart and TS. Dart announced a year ago and they're only now dealing the JS interop issue, so to most people its still only really interesting as a play thing. TS announced and from the looks of if we choose to we can immediately start using it.
I know Dart is more ambitious and maybe long term their focus on issues other than interop will be proved to be correct, but I doubt it.
TypeScript doesn't have JS interop: it is JavaScript. TypeScript is basically JS linter with a type annotation syntax. (And a few additional local features like arrow functions and class syntax.)
That being said, we know on the Dart team that JS interop is hugely important. It's just much harder for us to do. We've just announced a big step in the right direction: http://www.dartlang.org/articles/js-dart-interop/
I do understand what you are saying, had read similiar on Dart forum in past. Just to be dear I am not in any way saying I think the interop would have been easy, I do think without it Dart was a dead end for most people. It will be interesting to see how things proceed, whether the interop story that is now available lets Dart finally take off a bit in terms of usage and mindshare.
Yes. Google (and others) need to stop releasing half-baked products.
You release something half-baked, even if it gets up to speed down the road, people will still have perceptions of it being half-baked. The above exchange is typical.