How many people believe Star Trek is real? Star Wars? Are you sure there is no "force" and it can't be with us?
Futurama references aside:
https://en.wikipedia.org/wiki/Star_Trek_fandom#Religion
http://www.jedichurch.org/
There are some people who take it very seriously, even though it's fictional, just like any other TV show or movie franchise with fictional characters.
But to stay on topic, Kermit and Piggy are a part of that troupe of characters people really care about because they are performed so well, and that's what makes the difference in people's reactions here and around the internet. Would anyone be having this discussion if Ernie and Little Bit from Peppermint Park were breaking up? Nope.
At the end of shooting, Steve and Eric take the puppets off of their hands and put them away. Then they go home and have dinner, spend time with their families, take out the garbage and pay the bills, just like we do. It was the same when Jim and Frank did this years ago.
So, let's just enjoy the show when it comes on and hope that the quality of the work meets (and hopefully) exceeds our expectations.