Dartium doesn't need to be close to native, it just needs to beat every JS engine out there; in other words: the comparison should be in the same league. Last time I've checked it did beat them.
Actually it needs because it was supposed to compete with the mobile/ios/native apps not with javascript. I don't think anyone was thinking to replace javascript with something only slightly better.
If you are really looking for mobile/native development in Dart, I'd suggest you to check out Flutter (https://flutter.io/). It can achieve 60 fps on mobile apps, which is great in my view.
But I doubt that you are really interested in any of these. I've got the impression that you only try to find a justification of not using Dart, which is fine, but looks a bit weird when you are masking political decisions as technical ones.
I need someone to convince me that Dart is worth the switch and that it is safe for long terms investment. Having said that I geniunely tried Dart about 2 years ago. The plan was to try it for a small/admin app and then migrate the main app to Dart as well. Unfortunately there were issues with E2E testing; if I remember there was no Karma-like framework and on top of that the app froze several times on safari mobile. So at that time it was risky and it clearly had some technical issues. Now we know that the VM won't get into Chrome and it seems the new technologies(WASM, JS upgrades) put Dart in a difficult position.
Is there any reference/complex mobile webapp 100% Dart powered?
maybe for the mobile version (flutter is early stage, so i didn't expect Google to use Dart there [https://flutter.io/]. The last mobile webapp i worked on was just replaced with a native version which runs smoother, so i guess native development beats webdev at the moment).
How about with the web version for desktop?
The announcement showed advanced ui-elements: [https://lh5.googleusercontent.com/GRV687LnnWpFCpPcQ6vxjd_kEQ...]
So a primitiv result there would indeed be a disappointment.
It might still be work in progress. I guess they started 4 month ago with the rewrite?!
