Special Features on Blu-rays

[Canada]

Blu rays are the best of the best as far as home video is concerned. I was looking at Tombstone and the reviewer pointed out there were many features that were on the Vista Vision version that were not on the Blu ray. I for one am getting tired of studios putting out Blu rays that don't have as many extras on them as DVD's. I would love it if all the features were in HD but if I had to choose between SD extras or no extras I would choose SD in a second.

Unless Criterion or another studio did the special edition of the DVD why aren't all of the features from the DVD carried over to the Blu-ray.