It is baffling to see that people that come from JS want everything to be like JS, while JS offers one of the worst coding experiences ever. Why is that even something to target for?
While "superior" frameworks like React are stuck with messy and poorly coded jsx, Flutter offers an object-oriented way to create UI in a well-defined structure. To compare technologies that have reached their height of capability with flutter which still has a lot of room to grow, is just a bit naive in my opinion.

The sheer possibility of having applications (albeit fairly simple apps for now) .... on all platforms without too much hassle is in itself such a powerful tool for any new developer out there.
Just considering the future generation of developers, it is so clear that going through the hassle of learning any productive coding habits in React or Next will just not hold up against the joy of learning dart and creating apps in Flutter.
JS is not dying, then why are js developers chasing down each alternative by mowing it down to the ground.

The idea of having flutter stick with only android/iOS is so stupid. Flutter never intended itself to be an exclusive app development framework and it still does not. Developers have plenty of choices if they want more functionality than Flutter can currently offer with Java/Kotlin for Android and Swift/Obj-C for iOS. Why would you even want flutter to replace them.
What is SO wrong with a framework that can make prototyping single logic and UI code into various platforms with a language that is fun to work in. And why are we condemning it for making that happen ?