Booze.
I have huge chunks of memories missing and that ain't exactly a bad thing for my older, and sober, self. (Sometimes I still get flashbacks of blurry memories and it is very anxiety inducing. Booze memories are weird and were written to some corrupt cells or something that only pop back up under strange conditions.)
The media (Blu-ray, dvd, whatever..) didn't matter so much. Adding depth fields to existing media works, but it isn't exactly perfect. The tech should be much better now, but it took a fuck ton of manual labor to convert films to be compatible with 3D. Back when 3D TVs were being pushed, studios had to film movies in 3D as well, which took more time and more equipment.
Here is an old pic I took during the conversion of Titanic into 3D since it wasn't filmed in 3D from the start. Each frame needed to have depth fields mapped, by hand, in a room filled with jr level staff. This work was split across multiple studios.