That’s not necessarily a belief that holds true universally. Plenty of developers have found that React and JSX are two technologies that have beautifully matured outside of their initial home in the web browser ecosystem.
To use your phrasing, React and JSX are always going to be there regardless of what is fashionable for them to be wrapped around.
If you mean React Native, many of those devs are now adopting Flutter fashion, at least from the iOS and Android corners of the Internet I happen to move around.
To use your phrasing, React and JSX are always going to be there regardless of what is fashionable for them to be wrapped around.