People always blame the networks for their content, but ultimately it's the viewers who are responsible. Commercial networks need ratings to sell ad time and stay in business. So the shows that the audience wants to watch get renewed, and the shows the audience doesn't watch get cancelled. You can start out with the best of intentions to be a smart, educational cable network, but if your ratings tank and the advertisers won't buy time, you have no choice but to switch to more profitable programming if you want to stay in business. And that's why educational channels end up degenerating into pseudoscience and reality dreck -- because, sadly, that's what the public wants.
This is why public television is so important. The only way educational television can really work is if it isn't dependent on advertiser dollars to stay in business. This is why we need more government funding for PBS, not less like Mitt Romney wanted. And maybe more government involvement in other ways too. When I was growing up, there were FCC regulations saying that networks had to feature a certain amount of educational content, and so there were more shows out there that were actually informative.