The problem is that this only really works well for "documents". Most webpages are anything but "documents", even those that do mostly focus on text. Of course

The problem is that this only really works well for "documents". Most webpages are anything but "documents", even those that do mostly focus on text. Of course, HTML templating can help a lot with that: adding footers and sidebars and so on. But it's still no good for "web apps".