For 20 years, every movie we rented on videotape began with the disclaimer:
This movie has been modified to fit your screen.
A simple process to eliminate least relevant sides of the movie and focus on the action.
I hope it's only a matter of time till someone comes up with a reverse process for old SD TV shows and modifies them to fit our new screens.
It could make someone a fortune.
Except that you are taking an already crappy 480 vertical lines of resolution cutting the top and bottom off to make it fit a 16x9 aspect ratio so maybe what 320 lines of vertical resolution left, and then blowing it up to 720 or 1080 vertical lines. This would make the source look even worse than standard definition.