I think absorbing into React Router makes more sense when you consider that a) most of Remix was just RR, and b) Remix had at most 5-10% the users that RR has[0] (probably fewer). I think the "modes" distinction[1] within React Router is easier to understand and explain than a separate framework wrapping RR.

[0]: https://npmtrends.com/@remix-run/react-vs-react-router

[1]: https://reactrouter.com/start/modes