React Native isn't write once run everywhere - it's learn once run everywhere. And it interfaces with the real native widgets and has the javascript on it's own thread. That's anything but feeling right. It's more like Javascript bindings than a totally new paradigm.
That's nonsense. Javascript is certainly missing some features for mobile, but it's not because it is designed for "the lowest common denominator". It's because it's an open platform, and the standards committees and browser developers are really slow to keep up with all the devices that we have now.
Unity, on the other hand, works extremely well. Adobe AIR works well too. There are really awesome games made using both platforms, arguably the toughest kinds of applications to make "feel right". You can't just say the "Write Once, Run Anywhere" approaches are flawed when there are thousands of counter-examples on the app stores right now.
Facebook for example is releasing new versions every 2 weeks and every day I have updates for at least 6 of my apps. I also have built at least 10 apps for enterprise companies and provided you have decent CI have been able to turn around updates in less than a week. It is a different workflow that's for sure. As for Swift being a disaster well that's debatable.
Javascript and other Write Once, Run Anywhere approaches have always been shown to be flawed. They force the lowest common denominator. And on a platform like iOS where users are very picky about polish they will punish developers who have apps that don't feel right.