I don't think anyone is kidding when they say the twelfth of never. I suspect the problem was that the previous sets never sold as well as Buena Vista thought they might. People remember the Muppet Show being that series where famous guest stars played second fiddle to these bizarre puppets. They also remember the outlandish backstage plots - Glenda Jackson as a pirate, Dance Marathon, Brooke Shields as Alice in Wonderland etc. However, only those who are really familiar with the show knew what to expect with seasons one and two. Joe Public, on the other hand, didn't and was confused as to what they were seeing.You're kidding.
It happens with other archive TV shows on DVD and it comes about as a result of poor marketing from the distributor.