I do think CSS is meant to be pixel exact positioning tool, at least if you use pixel metrics. (Of course, anything that has images is pretty much forced to use pixel metrics because browsers suck at image scaling.)
CSS was also meant to solve the multidevice presentation problem by allowing overriding of the instructions based on screen type (somehow), so the pixel reign can probably be extended even to devices shaped like a david's star in due course. But as with all abstractions, you can spend a lot of effort doing something that probably ends up being a very small benefit. The only really good use case I've come across for @media is the ability to remove elements from page when printing, so far. Not very glorious.
All this CSS stuff is very complicated, and historically most of it didn't work reliably. Today it might work, but I don't care. As I admitted from early on, my attitude is best summarized in the word "apathy".