I think that that is part of the point with "modern" (however you want to call it) HTML: it should be declarative and layout-agnostic, and let the CSS do its thing regarding the various ways it should be displayed; this way the HTML is the same regardless of the actual layout of the page. Or at least it should be, in principle.
Just a reminder: csszengarden.com was created back in 2004 (I think). Zeldman's "Designing with Web Standards" came out in 2003. "Modern CSS" is over 17 years old. The CSS itself is not yet 24 years old.
