React isn't a way of structuring code though. It's a whole (huge) framework dedicating to making web apps/pages. And most of the time it seems to be used to replicate functionality that the browser can already natively do (for example, navigating to another page).

You want a good example of how a non-react website and its code might be structured, look at GitHub. At least from a user perspective, I've never had a problem using the back button or ctrl-clicking links while navigating GitHub - which is not something I can say of most other React and heavy-js websites.