What does this mean? There are plenty of big, native apps using React.

React is a web framework. You can put Native behind React, it'll never be.

React allows you to write custom renderer and React Native is a quick and dirty example of that custom renderer. The only reason it does not "feel native" is because Meta does not invest much into it and only subset of the "native" features is implemented in "native way".

It's "native" in that the wrapper is a native binary, but it's still a webpage.

React Native actually constructs a view hierarchy in the platform's UI toolkit, so I'm curious what you mean by "still a webpage"?

React Native constructs only single UIView by default and draw actual UI using poorly man browser engine using JS. This UI does not "feel native" to user, because it has wrong animation timings, scroll speed, border elevation, missing "native" gestures, etc.

That is certainly true of Flutter, which has its own rendering pipeline. React native, if you create a Button then on iOS you'll get an actual UIButton instance constructed, etc.

It is true for a few components derived from TouchableOpacity like Button, sure. That is NOT true for most other components. You does not have UICollectionView, UINavigationView (only solvable with third-party buggy components), etc.

With respect, literally the exact opposite is true. I think you're mistaking it with something else.

But everything in that view hierarchy is still drawn using HTML and CSS, and all the logic is implemented in JS, no? If that's the case, then that's not "native".

No, it renders native views.