Dave Rupert thinks version number bumps would be a good move for HTML and CSS, marketing-wise. I agree!
A single number bump replaces a mountain of marketing. Every discerning technologist knows it only makes sense to invest in technologies that are moving forward. To invest in a stagnant technology would be a dereliction of duty.
I think this has effected web technologies deeply. HTML5 was released in 2008 and its handful of new elements and APIs was a boom for the language. Even Steve Jobs advocated for it over Flash. Web Standards had won, Firefox and Webkit were our champions. “We need to upgrade to HTML5” was a blanket excuse for auditing your website and cleaning up your codebase.