I don't see this, or any other equivalent effort, taking off. It's neat, but CSS layout is a small part of the overall problem. Even setting side accessibility, which is a massive undertaking in and of itself, you have text rendering.

To get an idea of what you'd have to emulate, here are some (not even all) issues related to rendering text: https://faultlore.com/blah/text-hates-you/