I'm more interested in the future of "you probably don't need a native app".

It feels like browsers are closing the gap pretty well with things like IndexedDB, offline features, WASM, etc. Still a ways off, but seems like it's getting there.

I do worry, though, that it's not really in Apple's or Google's best interest to move that along.

Native will always be the best solution... Because it's native.

Technically best doesn't always win the market. I'd love not writing 3 versions of every piece of functionality.

> not writing 3 versions of every piece of functionality.

React Native and ReactJS are a move in the right direction.

I wonder if we'll get React NativeJS

Not sure exactly what you mean by React NativeJS but perhaps React Native for Web (https://github.com/necolas/react-native-web) is along the lines of what you are thinking?

Works remarkably well. It’s already used for Twitter’s mobile site