I meant using AJAX to transfer XML that gets inserted directly into the DOM. Of course that was never the only use of AJAX, but it used to be much more popular than it is now, and it's what Hotwire is trying to make popular again.

It's not quite the same though, there's a light framework involved for defining how the html is inserted, it's over websockets, new request types, etc.

But point taken, I recall using similar techniques a long time ago. I think the pendulum is swinging because front-end development has gone down such a rabbit hole with state management that people are wondering if they can remove all the overhead of redux, translating JSON, client side routing, etc. In most cases, they probably can I reckon.