There are many drivers towards HTML5/CSS3, but at least one of them is meeting the needs of designers, so obviously this is in the process of being corrected. Like most people, I've been pretty anti-IE, but someone pointed out to me that HTML5 actually standardizes a lot of features that Microsoft implemented years ago - shadows, gradients, glows, embeddable fonts, opacity, etc. Vector graphics? Microsoft: VML in IE5, 1999. Mozilla: SVG in Firefox 1.5, 2005.
Maybe if open source and standards-based browser developers had taken the lead in supporting designers' needs, they could have overtaken IE years ago.