Well if you think about it, the netflix UI is pretty much a bunch of documents. It's a gallery of images, and each image has its own document.
The DOM is a dinosaur unfortunately, it just gets the job done for most basic websites. CSS is also a language made for the DOM. The thing is, the DOM isn't required for a web page. Netflix could have coded up their entire UI on a Javascript 2D game engine and could have ended up with a faster app for sure. But CSS and the DOM make it much easier to work with text + links, that imo it's worth it for the performance drop of animations.
Not to mention the nightmare that accessibility would be if you were just rendering polygons on a canvas.
If this is the direction the web is going, I think it’s worth considering a shift to technologies better suited for the task (QML, for instance, looks like a great preexisting application-centric alternative to HTML). Old browsers that don’t support this tech would be taken care of by HTML polyfills until adoption of new browser versions is high enough.