A hard-nosed opinion, and a very opinionated article, but it's point is no less true. The Muppets aren't doing very well, and in a sense are has-beens.
Look at how many celebs clamor to be on "Sesame Street"- despite the changes (I haven't watched the show for years so I only know of them secondhand), it's still a very lucrative property.
Now look at the Muppets' recent projects- David Arquette, Whoopi Goldberg, and Jeffrey Tambor are about all the star they can get. No knock against them (I'm a big "Arrested Development" fan btw), but back in the day they had A-listers clamoring to be on TMS, and they don't have that anymore. The Muppets aren't a lucrative property, mainly because they're not doing anything and a lot of what they are doing gets drubbed by critics and a number of fans.
Personally, the last Muppet project I loved was MCC, writted by Jerry Juhl, whose involvement was gradually phased out from that point on. MT involved notable behind-the-scenes talent from successful shows, but not necessarily the right people for the Muppets, and (if memory serves) none of them with a variety format background. Variety shows have been long gone, and it's to the point that there aren't any people around who know how to do them right. A similar argument can be made for film musicals, seeing as there are a lot of unsuccessful ones up there with the successful ones. It is as though executives don't think that doing a musical requires any special qualities- that anyone can do it. Perhaps the same mindset has gone into Muppet writing- that any seasoned writer can do it, which is not the case. They have a style all their own- silliness with sincerity, and a balanced, multi-leveled approach to humor. Their best projects following Juhl's retirement seem to be aiming at this and some come very close at times. But IMO nothing has fired on all cylinders of late.
The Muppets, despite how much we love them, have become has-beens, and they're going to stay that way until the powers that be shape up.
David "Gorgon Heap" Ebersole