But doesn't it seem reasonable to use TypeScript for flutter now? If you are not a Googler, Where do you use Dart (outside flutter) in production for a purpose where it is better than TypeScript?
Flutter started as an experiment from chrome team, so their first language was JavaScript, when they move to dart they decided to write the whole framework layer in dart, the engine is in C/C++, so it seems there is no going back to a JS world.
https://flutter.dev/docs/resources/technical-overview#layer-...
With the Dart, they got a VM, GC and other tools and a language team that could grow Dart to suit flutter. They also got stateful hotreload, a Dart idea, which was something that the Flutter team didn't know they wanted.
Why? Libraries.
Of course, the Flutter team could build the toolchains they need themselves. Or they could just...use the up-to-par language they're already using instead of rewriting things for no real reason.
Take this survey with a grain of salt, because the results come from IntelliJ users, and IntelliJs most important and popular product is IntelliJ IDEA, a Java IDE (and other things)
So the results will skew in that direction for that userbase.
Then again, none of the responses here are outside flutter development!
Though, note I am the author.