Unfortunatelly this is the state of software these days - half-baked libraries + incremental improvements. This doesn't work in most cases. I wouldn't call it mistake though, open sourcing anything is a good thing.

The right solution is a library like this with proper cross-platform abstraction. Then you can simply compile css-in-js to stylesheets to have caching, therefore fully utilizing platforms capabilities.

Who cares whether css is written in css files or js files or whatever. Abstraction + solid tooling (compilation) + ide support is the way.