Funny how these things go in circles. I remember the time where many webpages were unstyled, letting you freely choose the font, size, colors, etc. in browser preferences. But that was considered ugly and non-user friendly. Now with various readability buttons we're just moving back to that.
Without custom CSS, you couldn't, however, fix the single most important readability issue about unstyled HTML: add reasonable margins and keep body width at the recommended 60–70em or so. Readability modes finally get that right.
Right. I forgot to mention that we also used to be able to resize the browser to the width we personally found comfortable for reading. I guess that's something reader modes still have to rediscover.
