CSS layout capabilites is a superset of what is possible with presentational HTML, so deprecating presentational HTML is not really the issue. Many of the crazy float hacks was to achieve layouts like expanding sidebars - the so-called "holy grail layout". But this could be cleanly and easily achieved with display:table. So why didn't people use display:table? Because Internet Explorer did not support it. Microsoft disbanded the IE team and did not develop the browser for many years, but the browser still had a big enough market share that developers had to support it.