That's basically the history of Flutter. The initial goal was something like "Web: The Good Parts" and the results of that experiment led them to where they are now.
As someone that’s using it, it is improving very quickly. Web support is getting quite good.
It has significant tradeoffs and fits some projects better than others.
React Native has quite a few benefits over Flutter. Especially if building for the web, I’d actually say Flutter is only usable now if you don’t build your web app with it. Which in my cost benefit analysis makes it miles behind RN, but of course, that’s why it depends.