Web Components are not a replacement for React. They are a thing you would use to build React if you were to do so today. To use only Web Components, you will be writing a lot of low-level code using the browser's API, or you will have to use a framework built on Web Components
For me it's a perfect replacement for React. I've been using it for years, and I'm much more happy about it than React. And I was already very happy with React compared to before that. I think it's the logical next step, but you need to unlearn some React concepts and relearn some Web Component concepts before you are really comfortable with it. But when you know how to work with it it's really super nice, and you'll appreciate better understanding the powerful browser and DOM APIs.
