Web Components aren’t an alternative to React so much as a complementary technology. Yes, you can build UIs without a reactive framework but it will involve compromises in expressivity, code organization, and whatever the Greenspun equivalent is for React.
Web components do not imply a lack of reactivity. JavaScript accessors, observed attributes, and a declarative template library give you as much reactivity as React. Photoshop and Chrome are built with reactive web components.
