[robertknight]

In general, no. React has been around for over 10 years now, and it generally remains popular and well supported. It is not going anywhere. Some sites will choose to migrate between React and Web-components based frameworks such as Lit for various reasons (technical preferences, standardizing technology stacks within an organization etc). Some sites will combine chunks of UI built with React and chunks of UI built with Web components (eg. by different teams within an organization). Others will create web applications which use Web components for style/DOM isolation at the top level, but where web components are built internally with React (which has various tooling and API advantages over WCs at the lower level).