@Benton12 said:

Look it was partially the film they used. It bored audiences. Badly!

Another major problem was the premise. It was too simple and unoriginal. The astronauts are supposed to be able to go back in time. Somehow. Utter nonsense of a premise--pretty much (though in all fairness "Escape from the Planet of the Apes" did have a similar premise). I say pretty much because astronaut characters Burke and Virdon never actually go back in time. They are technically just trying to. I would have written the premise a little differently if I was Art Wallace (show creator). I would have the space men wonder if it is indeed Earth in the future or a parallel planet of some sort to Earth. Think of it. The experienced Virdon could say to Burke "If we are in the future we have no way possible of going back in time. Einstein's theory of relativity only showed how to go forward not back in time as well. But if this is just a mirror planet to Earth (perhaps like on the other side of the sun) maybe we can get back to our Earth." then adventures could have been about their attempts to see if it is the same Earth or a parallel one. Say, Burke finds a very old book claiming the 5th president of the US was John Addams when he was more like the second president in our earth. Virdon however suggests that while the bad info may indeed be valid in proving a parallel planet that it may also be a typo or it was written as the apes took over the planet and the writers may have lacked better human knowledge or that some considered John Hanson first president and maybe Hanson's memory got more popular on earth after the astronauts left.

My premise would have been more interesting by far.