I just watched the relevant part of the interview and I will say: Solow doesn’t come off in the interview as someone with an axe to grind against a man who had been dead for twenty years at the point the interview happened. The man does come off as someone in complete control of his faculties. He doesn’t have any proof and is not willing to get into it. What he says exactly is:
So I, uh, we now had an order. We needed a script. And Gene wrote the script… which I have some strange doubts about but I’m not going to go into it here because it involves another person who has since died. Uhhh, ‘cause I believe that that guy did most of the script. Uhhh, and he would never admit it to me. He’s a friend of mine. He said, "I’d rather not go there, Herb." I said, "I understand. Fine. It’s fine.”
I think it’s more than likely that yes, Gene Roddenberry did the lion’s share of work on “The Cage.” But, things to point out:
Gene Roddenberry was the kind of man who would sell his own mother out for a buck. In order to get some money for the publishing rights of the
Trek theme song wrote terrible lyrics and upset Sandy Courage in the process.
The man had a huge ego. A prime example of this is stated in Cushman’s
These Are the Voyages: Season One:
Since it was now known that either this episode ["The Man Trap"] or "‘Charlie X" – the only two episodes ready, other than the second pilot film – would be the first to air, Roddenberry arranged for the opening title credit on both episodes to read “Created by Gene Roddenberry.” After these two programs, and some pressure from the studio, his name did not appear in the opening title sequence … until the next season when this became the norm.”
I don't believe it was general practice to do that in the 1960s. At the very least not at the top of the credits before the cast's names. I mean, on September 8, 1966, who knew or even really cared who Gene Roddenberry was? It comes off as a ploy to placate an ego.
As others have said, Samuel Peeples helped Roddenberry develop the concept. He also wrote the second pilot. They had an existing working relationship.
“The Cage” is a solid script. Roddenberry is not a solid writer. As others have said, he’s an amazing script editor. But his own scripts have always been mediocre at best. "The Omega Glory" is arguably the worst episode of the original series. The episode had been rejected many, MANY times before it reached air. Someone commented above that perhaps he had more time to work on "The Cage." Maybe. But I have another theory. If you’ve read the initial drafts of
Star Wars, they’re horrible. And nothing like what we got onscreen. If you look at the prequels, you know George Lucas, when writing on his own, cannot write believable dialogue for the life of him. He did have help from Gloria Katz and Willard Huyck. Does the writing credit for
Star Wars include those two names? Nope. Just Lucas. But the script was much better with their help. Point being, its not unheard of for there to be uncredited polishes on scripts.
Putting all of this together, I believe Roddenberry wrote the concept, the treatment, and the majority of the subsequent drafts of the script. BUT, I believe that either Peeples and/or other writers helped greatly in fleshing things out through notes, suggestions and possibly even an uncredited polish or two. While Roddenberry did keep impeccable records, because of the fact that he was a known, for lack of a better term at the moment, scoundrel, I could see him destroying those records showing others’ help along the way for the pilot, in order to keep
Star Trek created by Gene Roddenberry. That last part is pure supposition on my part and I do admit that. But I wouldn’t put it past the guy. Or maybe whoever Solow's friend is was just doing Roddenberry a favor. Or maybe Gene had something on Peeples or whoever helped write the script. Hollywood isn't exactly a moral place.