And what's wrong with that? It works good if you're building an SPA in React.

You asked if react-router team sold courses, they sold consulting services. Seems like a conflict of interest to sell consulting on a tool you built while introducing breaking changes (but hey if you need quick help throw us a few dozen grand).

I guess that's fine for you but it's very smarmy IMO.

They also post (free) documentation how to migrate from the previous major version