I was also guessing it would be lossless, but they could theoretically do their best, and not have to spend a penny more to deliver both compatibility and sound quality on the same media.
Since there are still Blu-ray players being made that play DVD-Audio discs, it's not entirely unreasonable to just throw some files into AUDIO_TS.
Yes... I suppose it was all just a fantasy of mine. It's just so miserable that someone bothers to make a great mix, and then it can only be heard in DTS. Isn't technology supposed to perpetually advance, not go backwards?