An over the range MW has to act as the fire safety non combustible surface over the range as well as the hood. With standard ranges being 30", that means that the whole surface above the range has to be non combustible. That's 30". Even for a 24" compact range, that 21 inches of width that the LG provided wouldn't be wide enough to work as the required non combustible surface. It's not surprising that it was discontinued. THe real surprise is that it was produced in the first place.

That LG 22-inch over the range MW is specifically for RVs and boats, not for home kitchens.

Hollysprings explained it well why such a MW is not to be installed over a home range with a standard width of 30".