I think this is because HTML, CSS, vanilla JS, browser DOM implementations, and networks have all gotten better. Whereas the complexity/churn around JS tooling (and to a lesser extent React) has grown. Additionally, the overuse and abuse of React, to the point people are making largely static sites with React, which is largely a total waste of time. This has caused people to take a second look at their options, which should be viewed as totally natural.
I don't think of it as "going backwards", so much as reassessing and questioning the tools we are using and using the best one at hand. I don't know of anyone who suggests using hypermedia for all applications, just use it where appropriate and use React when simpler technology falls short.
