I can't speak in general, but there is one thing I vaguely remember being on the React roadmap as part of the class->function switch that AFAIK never happened (

I can't speak in general, but there is one thing I vaguely remember being on the React roadmap as part of the class->function switch that AFAIK never happened (at least it hadn't last time I did a lot of React, which was years into the switch): Because they were pure functions based on props, React-the-framework would have the class-based shouldComponentUpdate built into it and using function-based components everywhere would get a free performance boost. Instead nowadays people who started with the function form don't know shouldComponentUpdate ever existed and all their React components constantly rerender.