As far as i know the video qualiy has to suffer from a bitrate starvation and look like shit to fit a full PCM track on it, supposedly even if you strip out all the extras and other audios already on the dvd it still won't mux right, from what i've heard anyway.

Single layer dvd's and dual layers are short on space. Notice how for the first time since laserdisc movies are getting robust audio on blu ray.

If you did a high quality encode on blu media you could most likely use the HD video broadcasts and the gout footage upscaled and include all the audio tracks lossless. Create a perfect hybrid by cleaning up and color correcting the whole thing. So far no on has done this as the work would be ludicrous in the extreme.

At what bitrate can the human ear not notice a noticeable difference?

I have read that people cannot notice a difference audibly from a 2.0 dolby track and a PCM track, their mind knows the difference and they can check the bitrate numbers but how much can they actually hear?

I mean can the human ear really appreciate a 7.1 Lossless HD audio that is thousands of kbps.