For some older movies, there may not be a "right" format.
Take the film Back to the Future. It was originally released in 4:3 format. When it was re-released a few years later, it was touted as "Now in Wide Screen". In reality, the film was cropped on the theater's projector; it had the same horizontal image as the original release, but the top and bottom of the picture were masked off.
Some films were actually shot in 4:3 format so that the TV image would be proper. The films were distributed to theaters in cropped format to provide a wide aspect ratio, but the 4:3 image was used for the tapes and Laser Discs. Two examples of this are Backdraft and The Abyss.
The biggest problem I see with NetFlix (and other services) is that many (maybe most) people in the country can't use it because the internet connections are so shitty.