It might well have been ABC that was cheap.
For way too long - until 1971 - my hometown TV market had just two stations, NBC and CBS affiliates that shared the ABC secondary affiliation. But most of the ABC programming wound up on the NBC affiliate, including ABC's Movie of the Week. The local newspapers' "action line"-style columns featured frequent complaints about the fact that the Movie of the Week was in black and white. The station's explanation was always, "that's how ABC sends it to us and they refuse to send it to us in color."
Where I spent part of my childhood, it was a one-station TV market, though in many areas one could get two Des Moines stations with an outside antenna. The local station was an ABC affiliate, but carried a few CBS daytime programs. Then it filled the open time on its schedule in the late afternoons with ABC programming that it didn't clear from the usual network feed. It couldn't tape the ABC programming because its microwave relay to Des Moines was occupied with the CBS feed. So ABC supplied programs such as "Dark Shadows" and "Let's Make a Deal" to the local station...on kinescope. In the late 1960s. In black-and-white. Finally, KTVO prevailed upon the network to provide videotapes. Which ABC did...in black and white. The notable thing about that was that the audio quality on those tapes was better than what you'd get from a network feed, in the days when network audio still was limited to 5 kHz audio response.