I'm not sure why Hyatt rejects the idea that execution of stylesheets should not be similar to execution of client-side scripting. Almost any style behavior that can be expressed in CSS can also be expressed in Javascript--sometimes much more torturously, sometimes more elegantly. So why NOT treat styles as a set-based, declarative variant of scripting?

Furthermore, the presence of a style reference is an explicit hint to the renderer that some of the default rendering behaviors are inapplicable; any further rendering work undertaken until the styles are retrieved and interpreted is likely to be wasted effort.