“Astro introduced something called "Island Architecture," and once you understand it, you'll wonder why we've been doing things any other way.
…
Your pages are static HTML by default, and only the bits that need interactivity become JavaScript "islands."
(From https://websmith.studio/blog/astro-is-a-developers-dream/)
We’ve gone full circle folks, all the way back round to “generate HTML on the server and progressively enhance with JavaScript”.