In his book "Star Trek Movie Memories" William Shatner describes Roddenberry's career in the early 70's.
With regards to "Planet Earth", it's stated that the network passed on the series because it was felt that it could only afford 1 expensive science fiction television series.
The other choice was "Planet of the Apes". Because of the franchise success of the "Apes" films, it was felt by network bigwigs that an "Apes" TV series was the better bet and had more of a chance of being a hit.
As it turned out, the "Apes" series tanked after 13 episodes.
Hal
With regards to "Planet Earth", it's stated that the network passed on the series because it was felt that it could only afford 1 expensive science fiction television series.
The other choice was "Planet of the Apes". Because of the franchise success of the "Apes" films, it was felt by network bigwigs that an "Apes" TV series was the better bet and had more of a chance of being a hit.
As it turned out, the "Apes" series tanked after 13 episodes.
Hal