In response to the muppet show being revived and well it applies to even this..
A major difference I think between the muppets of old and muppets of news are cameos/human actors in them. Think about the guests they had on the Muppet Show-Ethel Merman, Julie Andrews, Bernadette Peters, Joel Grey, Ben Vereen, Gene Kelly, and okay of course I have a special love for the Broadway ones but even great people in other areas--Elton John, the Star Wars actors, John Cleese, Linda Rondstadt, etc. People with amazing talent, some of which were known for so long.
When you look at the early muppet movies...Bob Hope, Steve Martin, the puppet guy who I can't remember, and oh you all know the names.
The humans they get to work with the muppets just aren't waht they used to be, and that's attributed to the times. While I think a muppet show would be great bringing on all the Broadway talent now, it just wouldn't work because almost no one on Broadway is well-known outside our community. And there just aren't great legends around anymore, so who do we get working with the muppets? Ashanti, Jeffrey Tambor, Jessica Simpson, I wouldn't be surprised to see Britney too...the muppets just don't work with them. And also in some of even the more recent movies(Christmas Carol, Treasure Island and now Wizard of Oz) the main characters have been humans, while in all past movies the muppets were the main characters with mostly cameos by humans, who were way more talented than people available today anyway. Okay rant over.
And well...I'm sure the death of Jim Henson, the disinvolvement of Frank Oz and lots of other veteran Muppet actors/writers, etc. also have contributed.
"If there was a Mount Rushmore for Broadway scores, "West Side Story" would be front and center. It snaps, it crackles it pops! It surges with a roar, its energy and sheer life undiminished by the years" - NYPost reviewer Elisabeth Vincentelli