> React isn’t just "winning by default" It's winning because at the core it's just JavaScript function composition.

This might be just a rationalization. React might be "winning" (whatever that means), because it was the first proper component-based library, when its competitors (Backbone, Angular, Ember) were large, slow, and clumsy, and still struggling with the concept. Plus, developers back then were easily impressed by the word "Facebook", which meant a large tech company that probably knew what it was doing, and served as a guarantee of good quality. So it had a tremendous head start and good marketing. If Vue, Svelte, Solid, or Lit were there first, who knows if React would be "winning" now.