Captain Shatner wrote:
Personally, I think "The Cage" was one of Star Trek's most interesting episodes. It's much deeper and introspective than, oh, say, "And the Children Shall Lead". The question is, why was Pike dropped, but Nimoy retained as Spock? The pilot set up everything, a chain of command, and even romantic interplay between Pike and two of his officers. (Ironically enough, Gene repeated that theme of "long-running relationship" with Kirk and Yeoman Rand for the first season.) But by the next episode, (the one with the salt-eater, which wasn't nearly as deep) Pike and his entire bridge crew (minus Spock) have disappeared. Of course, Pike reappears later on, but even so...why did Roddenberry decide to drop him?
He didn't drop the character, he changed the characters name to James Kirk because, as noted, they had to recast when Hunter declined to do the second pilot. Perhaps in the back of his mind Roddenberry had already considered using the pilot as a way to cut costs.