I wanted to ask/comment on several things but I'm afraid if I start trying to copy and quote I'll just mess up, so let me just ask and anybody who knows the answers can chime in.
1st question: Piggy ruin the muppets? HAHAHAHAHA! ! Who in their right mind thinks Piggy has ruined the Muppets? If that's in print I want to know who was brave enough to put their moniker on it! Come on--give a source. And sure, I know not everyone likes every character--that's okay. But ruin? Oh, please! What twaddle! She was the superstar they hitched their wagon to--the first break-out star.
2nd question: I'm going to ask a question, assume I know the answer and then comment. (That way if I'm wrong, you can all say "Nanny nanny boo boo!") Someone mentioned that Piggy didn't always sell as well other characters when they made one of each. I'm going to make two assumptions: Part of this is due to a gender difference in buying patterns and part of this is due to the fact that--of all the Kermit's I have (including the obvious knock-off with webbed hands) Kermit still looks a lot like Kermit. I have all sorts of Piggy merchandise that doesn't look a thing like her. Also, while I have joyfully snuggled with stuffed Gonzo, and a variety of stuffed Kermits (I SOOOO need a Fozzie), I wouldn't dream of snuggling my Piggy dolls. Buy clothes for them? YES! Design and sew clothes for them? Oh, YES, yes. (I even have FRIENDS who buy clothes for my Piggy doll--the latest being a red feather boa). But she is not a toy in the same way. I can't quite explain it, but I know if I hugged Kermit in real life (or Gonzo or Fozzie or Elmo or Grover or Big Bird, for example) they'd hug me back. Piggy might say, "Did I TELL you you could touch me?" It's...she's a diva. She inspires AWE and FEAR, but not snuggledom. So I don't think she makes as good a snuggle toy (unless you're a frog). When it comes to models, well, I respect the hobby and it's meticulous attention to detail and order, but it is a predominately male hobby. (I'm not going all sexist--I'm talking statistics here. This type of collectible just attracts more men than women.) And I think that it is more interesting to collect different versions of Kermit (and Batman) than it is to collect, um, (whispers) girl dolls.
Um, about the fad comment. I think you are mistaking the use of the word. I think that the muppets might arguably be a part of popular culture--like Star Trek and Batman--but they are not a fad. Bell-bottoms were a fad (thank heavens). Where's the Beef was a fad. Alf was a fad, bless him. Funny and irreverent but a fad, just like, "What chu talkin'about Willis?" The Muppets are one of the few groups who can claim to span several generations not only in popularity but in production of movies. The Muppet Movie was over thirty years ago--the MWoO not so long ago--same characters, um, sortof.
Someone else commented about how Piggy always steals the show when she's on. It's what diva's do. A perfect example of this is in The Great Muppet Caper, when Piggy ONLY gets to interact with Kermit in a genuine way, while ALL the other muppets get to interact with each other more. Even in the few and brief crowd scenes, Piggy is just with Kermit--like he's her interpreter or something. This is a tremendous example of how hard it is to use a "love interest" in an ensemble show--that's why all of Captain Kirk's women died or left at the end of the show, and why all of the Cartwright boys remained single. The fact that Piggy has remained both a love interest and very much a part of the cast is a testament to her great popularity--even the people who are anti-frog-monogamy have to grant that Kermit is more interesting when she's around. Doubt me? Watch the fight scene in TGMC. Or the scene when they pick Piggy up hitchhiking beside the road in TMM? Or the scene in MFS when Piggy shows gets into a fight with...well, pick someone. Or the scene in Muppet Treasure Island when she arrives on an elephant. Or the scene in MCC when she threatens to deck Mr. Scrooge. Or the scene in TMTM when she and Kermit have a huge knock-down drag-out fight in the middle of Central Park. Or...but I'll spoil all your fun finding your own.
Yes, yes--I know I've dragged you all kicking and screaming off the main topic, which was the bear and the frog, not the frog and the pig. But we all have to play to our strengths, so I'm playing to mine! Forgive me!