This was because its frequency spectrum was assigned by the system to a major UHF television station, which meant it had to relocate to another new public frequency to broadcast.
In big cities, being a die-hard viewer of this kind of Grade-A television station meant one had to be psychologically prepared to search for the station's signal every day upon turning on the TV.
In less populated areas, due to the sparse population and the lack of major stations, Grade-A stations managed to survive by airing various odd commercials for local businesses, such as all sorts of miracle drugs, farming implements, car repair shops, and the like.