And how exactly would you go about TFA's example of embedding the web ui inside a Golang application with NextJS?
I can think of LOTS of examples where you'd be better off with straight static server with React and a separate API server... pretty much anywhere you are doing a web application and don't need/want SEO/Bots.
The majority of react sites nowadays are just NextJS. It might be that the future of react based applications isn’t react, but nextjs.