The difference is between games that use vertical FOV and games that use horizontal FOV. LFS is the latter.
When the screen is wider, the same FOV will cover the same distance, therefore you will see less vertically.
To display more horizontal, you should just increase the FOV. This will distort geometry more as you are squeezing everything down. There is no way around this. Any option to "add left & right" areas would do exactly the same. The only way to remove all distortion is to use a physically correct FOV, but most people prefer to see a bit more. The usual FOV is also very distorted but you are just used to it.
LFS also has options for additional left & right viewports for triple (or more) screens. These can be angled to match the angle of the display which reduces the distortion a little depending on the FOV, however on a super widescreen display you'd be able to see the seamline where the viewports touch.
If you adjust the horizontal FOV to match the same vertical height in LFS, the same area covered by the original screen and the new screen will have the same distortion, not more, not less. The distortion only appears more because of the extra area which wasn't rendered before.