As the cost to make just about any television programming skyrocketed, so did the cost of making a pilot. The costs became less tenable considering that most of these pilots would never see the light of day. (Even a show that got picked up might not have a usable pilot.) The television networks were literally throwing away millions of dollars on programming that was not intended for broadcast.
How could the networks try to recoup some of their losses? By airing the shows in the summer offseason. CBS introduced a show called Summer Playhouse where it could burn off its unused pilots to at least make something from them. ABC actually tried to do something greater with its unused pilots- it ran many of them during the regular season as Love, American Style. While most of the episodes were comedic pilots, some non-pilots were mixed in. Despite being a place where failed pilots were supposed to die, it gave a very famous, hugely successful show a second chance. Happy Days was originally rejected by ABC and its pilot was burned off as an episode of Love, American Style. This successful airing would result in the show getting picked up.
It was easy to string together half hour sitcom pilots and find a place for them on the schedule. It was often difficult to do this for hour long dramas. It soon became common for networks to produce dramatic pilots as made for television movies. During the heyday of the Movie of the Week, it was easy to find room for a two hour pilot. Such was the case in 1987 when NBC aired Bates Motel, a planned spinoff of the Psycho franchise. After the costly pilot was rejected by NBC, it recouped some of its investment by airing the pilot as a film.