My point was that working with analog signal is not a good thing, and is going to affect the image quality. No need to try to start a debate about it, wait until the device is available and we'll see.
Neither nvidia or ati make the cards themselves so it is propably mostly up to the card manufacturers. Though there propably are some minimum requirements on the quality of the components on the card, at least they used to vary from cheap junk to ok in older cards but all seem ok now. And for the card manufacturers it propably isn't a question of being able to do it, but if it is worth it to put in expensive components that will be useful for only a minority of their user base (for "average" consumer cards).