You hit the point on the head when you say the page from 2002 still works (it’s html and files and a bit of js that enhances). Take a page written in modern style today and it won’t last more than a handful of years because it’s likely not a page, it’s an application.

The modern web is worse because it is made of opaque applications instead of HTML and text and images. You can’t remix websites today because they aren’t even web sites. And that’s bad.