More then one answer applies.
As you mentioned, some menu's come from a server. Such as the vod menu, amazon, rss feeds and what not. And those apps would have to be updated to be in HD, but would not match the main premiere ui even if they were in hd.
Other menu's, like the to do list, system information, and setup are still the sd ui. They could be made into the hdui, but haven't. And we really don't know why definitively tivo has not done this. Could be rush to market, could be many other reasons we have not thought of. We just don't know.
As you mentioned, some menu's come from a server. Such as the vod menu, amazon, rss feeds and what not. And those apps would have to be updated to be in HD, but would not match the main premiere ui even if they were in hd.
Other menu's, like the to do list, system information, and setup are still the sd ui. They could be made into the hdui, but haven't. And we really don't know why definitively tivo has not done this. Could be rush to market, could be many other reasons we have not thought of. We just don't know.