Network television does some strange things.
In the 1960's, they beamed James T. Kirk up one time too many - and he was permanently beamed down and out. The original Star Trek was a thought-provoking show, obviously building its audience slowly. It's just that the network didn't have the patience for it. They wanted instant ratings, and instant profit. Only after NBC canceled Star Trek , and it went into syndication on local stations all around the country, did it flourish into the franchise that it is today.