Flutter seems to have been gaining a lot - React Native is still popular due to size of the web crowd who refuses to look outside their little ecosystem box. But mostly, companies have been reporting that Flutter is much easier to maintain and much easier to reliably deploy across devices - it also doesn't suffer from NPM hell / dependency rot in the same way RN projects do.
I'd say both are on about the equal footing these days.
> the web crowd who refuses to look outside their little ecosystem box
I mean, we usually don't require other developers to actively work in 3 different stacks because there are theoretically better languages around the corner. In fact we even make fun of premature fanboyism such as RIIR.
Today, the web works for most purposes, but when it doesn't, you may need native apps. It then makes perfect sense that people can reuse skills, ecosystems and tooling. From a UI perspective, any modern web rendering engine can do pretty much anything GUI fast and consistently.
Dart is a tiny language in comparison, and last I checked Flutter's web target backend used an opaque canvas element for all rendering, which wasn't just terrible for accessibility but also super laggy. I am still excited about Flutter but they have a lot to prove before I'll frown at the web folks.
I would say that the web does not work for most purposes unless I ignore the horrendous architecture that is imposed by using it.
I bet only 1% of developers these days have written a native or desktop app. If they had, there would be a gravitational pull moving away from defaulting to the web. I can hit any API from a Swing or WPF app and look damn good doing it with blistering performance.
It shows whenever project owners start asking developers to work around or prevent the use of browser based navigation like the back button.
The browser is like a hand grenade being rolled under a software project. The ultimate shitty dependency.
My perspective is the opposite. Flutter does have a super nice dev workflow, but it's quite limited in how well it can integrate with the underlying platform and hard to extend if you need to step outside of what's available. On the other hand react-native is really maturing and has addressed most of the issues that people had with it. And is now expanding on to the desktop too!
I'd say both are on about the equal footing these days.