Initially, cable television aided the penetration of the networks into markets (like Pennsylvania valley towns or areas of the Intermountain West) where no local affiliate could be received.

As soon as the industry began to grow in urban markets, the networks took care of their own interests by pushing the FCC to mandate "must-carry" rules for local over-the-air stations. This further increased network penetration, especially in markets with a mix of VHF and UHF affiliates, as now all three networks were on the same footing with viewers unable or unwilling to tune in UHF stations.

The rise of superstations and cable-only networks came much later, when the industry was so established that it couldn't be fought. By that time, the old restrictions on network series production had been relaxed, and the networks saw new opportunities with brand extensions (like MSNBC) or selling content to superstations and cable networks.