"a world where the primary purpose of a website was to serve documents"
we are still living in this world. and i don't mean it snarkily. beside some maps application, most of the web is still about reading stuff, and it doesn't need so much cruft. it's getting more complex just because developers prefer complexity over simplicity.
De facto it's a web app, not a document, world. Have you tried browsing without JavaScript recently? It's even worse in this AI era when content sites want proof of work, only available via JavaScript.
we are still living in this world. and i don't mean it snarkily. beside some maps application, most of the web is still about reading stuff, and it doesn't need so much cruft. it's getting more complex just because developers prefer complexity over simplicity.