Ok, but even if transformations take place on the server, accessibility can still be preserved. In theory, yes. In practice, no. The third is undesirable, while the fourth is impossible in practice. Besides, caching suffers.
Semantic markup is dead.
RDF is important, but will not replace semantic markup. That has never been the intention of W3C Metadata efforts. But, in order to do high-quality printing we need transformations. CSS doesn't have transformations and is therefore unusable. High-quality printing is very hard, and can't be done without looking at the shape of the glyphs.