I think Boxee and Roku both have solid platforms and are very forward thinking about their respective ecosystems. The challenge is that video content producers are not there yet. Content producers are not their because adoption of these ecosystems have not yet reached critical mass.
At this point I think the entire industry vertical is more concerned with growing the pie rather than maximizing the slice taking their taking of it.
This tv ecosystem trend is happening, but right now it looks like the iOS App store in its infancy. Lots of potential. The difference was the App store rolled out to millions of existing phones at once. None of these platforms have that scale yet.