As I stated above, it's my personal opinion on the matter. I've used both of those libraries in a medium-sized project and they don't work well. Simply linking to libraries and saying they exist is hardly making a point.
I have used both of those navigation libraries in medium sized projects as well. This is the section that struck me as overstated:
"The last time I checked there was still no reasonable, scalable way to do complex navigation on the platform. Most third-party components are unusable six months in due to API changes."
The links are counterpoints to the complex navigation issue. Showing that libraries exist and can handle complex navigation. If you want to argue that they are going over rapid change, which is true, then that is another thing. But I'm gonna disagree with the blanket statement of "there was still no reasonable, scalable way to do complex navigation on the platform" as overstated.
As for the second point. I assume what you mean by 'third-party components', is actually third-party native modules. In which I agree the API for them doesn't seem to have stabilized yet so there is a lot of churn in native modules. But a lot of third-party components I have seen continue to work in newer versions of React Native.
