I don't know much better than you, but here is the general understanding that I've picked up: HTML and HTML2 were developed by developers (via the IETF). HTML

I don't know much better than you, but here is the general understanding that I've picked up: HTML and HTML2 were developed by developers (via the IETF). HTML3->HTML4->XHTML and CSS1->CSS2 represent increasing control by academics in committees at W3C. HTML5 and CSS3 are the result of fed-up actual web developers stepping up. What gets implemented in browser-specific extensions is some combination of governing committees and developers actually willing to write the code.