Those that hate Trek being shown in 4:3 so much need to learn how to zoom or stretch the image on their widescreen televisions until it fills the entire screen. Problem solved.
Not really because there's a hitch with doing that. It distorts the picture. Now, usually TV's stretch the picture in a "smart" way that stretches the edges more than the center so the picture usually isn't too out of whack so I'll admit on the DVDs I stretched the picture and it looked, by and large, fine.
But the BluRays are matted with actual black bars on the sides (on the DVDs there was simply no image on the sides at all leaving "white bars" on the side an effect of the TV getting no picture information from the source) so when you stretch the black bars away the "smart stretch" effect is rendered ineffective since the black bars are stretched away leaving a highly distorted picture.
Zooming in crops the top and bottom of the picture and can have many complications not to mention showing more grain in the picture.
Again, I say just cope with the black bars on the side of the screen and stop obsessing with "filling the screen." The picture on the screen is the same one you enjoyed 25 years ago that should be more than satisfying.
Stanley Kubrick disliked any form of black bars. He felt these distracted you from the viewing experience and composited accordingly. He shot in 4:3 (for 4:3 TV sets) but anticipated the widescreen crop for theatrical presentations.
If you're distracted by "black bars" on the side of the screen you may have attention issues. I find no such distractions when watching TNG on BD. Just like I'm not distracted by the black bars on the top and bottom when watching a non-16:9 movie on my TV. (Which is a majority of them.)
Are you referring to "pan-and-scan," in which movies shot in CinemaScope or 70mm widescreen were cropped to fit the old 4x3 TV screens? Yeah, that sucked. But the only alternative back then was "letterboxing," which shrunk the image so small that it was sometimes unwatchable.
"Pan and Scan" is a slightly different technique for converting things to 4:3. There's cropping the image to fit the screen by centering on an area where the most action was taking place and then there's "pan and scan" where false camera movies are added (literally "scanning" the picture) to fill 4:3 but done in times where more image is needed than can be displayed (for example two people on opposite sides of a table talking.)
Usually when a non 4:3 source is made into 4:3 a combination of techniques are used, pan and scan often needing to be a choice for films shot for some of the wider formats.
There are "some" movies that where shot with 4:3 in mind where horizontally the picture can remain the same and to convert MORE information is simply added to the top and bottom without revealing production elements (in most cases, there's a couple instances where this doesn't quite work out that I can think of.) This was largely done in the 80s and 90s when home video was popular and most people wanted pictures that "filled their screens."
Pan and scan is ugly. The false camera movies can be very, very distracting.