In Treatment, good show from HBO, 43 episodes per season. http://www.hbo.com/in-treatment/ . Just saying that although unlikely, it is possible and we don't even have to go look for obscure shows outside the US.
Regarding price, I have to disagree, there is a psychological price perception, based on what you feel that you're getting. I would never buy a single tvshow season for $100, as I would never buy a music album for $50.
From the producer's point of view, producing a tvshow episode is expensive, therefore it must be priced accordingly.
From the consumer's point of view, watching an episode is an ephemeral experience that is rarely repeated.
So, in the consumer's mind, an episode shouldn't cost three times more than a $1 audio track, when the track will get tens of listens and the episode will get one or two viewings.
In the end, the consumers would be right, but producers are fighting very hard to defeat the "the customer is always right" theory.