That was my point -- there is zero technical reason HD cant be delivered to desktop linux. Netflix shows do it, and so do a small number of other TV shows and movies. The vast majority of content, however, is limited to 480P. Presumably for licensing reasons only.
The most irritating thing is that "HD" now costs extra, and there is zero indication linux clients cant get the paid for HD content. I watch Netflix via Roku maybe 5% of the time, so mostly Im getting less than I pay for.