There have been three failed broadcast networks on American television. The first to fail was the DuMont Network.
DuMont actually predated ABC; in fact, ABC originally produced programming for DuMont. DuMont originally made television sets, but they were slow to move because programming was scarce. DuMont decided to start up its own network to produce the programming they felt was needed in order to make their television sets move off store shelves. Consumers eventually did embrace television, but not DuMont's programming. Due to this and many other issues, the network eventually folded, leaving ABC, CBS and NBC.
The big three solely dominated broadcast television until 1986. 20th Century Fox had somehow arranged a scraggly group of affiliates that were hungry for programming. They decided to start up their own network, gaining an exemption from the rules that applied to the other networks. Against the odds, Fox thrived. The FCC soon relaxed rules for all networks, which threatened the studios that were not aligned with networks. This worried Warner Brothers and Paramount who started up their own networks- the WB and UPN.
Both networks had a rough start, though UPN had luckily been granted a gift from its parent studio; a new Star Trek series that proved to be a stable presence. The WB used its famed Looney Tunes characters to establish a firm hold on weekly afternoon programming. Its prime time schedule was a different story. Eventually, it became unfeasible for the two networks ro exist as separate entities. They were both shut down and combined into one network- The CW.
