It is my impression that there was a few years ('95-'98?) when recievers were available with only Dolby Digital decoders, and no DTS capability. Also, only the first generation of DVD players offered no DTS output. It is also my impression that the people who bought these early products would be most likely to replace them with DTS capable equipment, especially since prices have gone so low. So would it work if studios dropped the Dolby 5.1 track from discs with DTS? We could then have a Dolby 2.0 track, and a DTS 5.1. On a disc like Pearl Harbor, that could make a huge difference! How many people have a 5.1 setup, but no DTS capability? Again, my reasoning is that having both is slightly redundant, (especially on Superbit titles).