Michael and Ryan have always been about trying to make money from their React expertise. They literally created a company called React Training: https://reacttraining.com/team and have had a fairly lucrative business doing workshops for years.
No harm in trying to get folks to pay for a framework. It doesn't seem it worked, but I can't fault them for trying!
React Training worked really well, was very profitable till Covid shut it down. Obviously not a scalable startup type thing but still a nice little business.
Apropos of which, it always baffled me how bad the React Router documentation was, given that the company name was react-training. It was like an anti-ad.
Some could argue the just okay docs were driving consulting business. Even the TFA mentions they started conversations with them because they were using react router! :p