He's 83, so he's held off retirement for a long time. (Fran Brill retired in her 60's) But he still visits the set frequently. Even though he's not performing. I'm glad that he's still involved by supporting Matt, Eric and his fellow muppeteers. However, even though he really just retired, I wouldn't rule out the possibility that he reprises his roles for something special regarding the 50th anniversary of Sesame Street. Also, he still performs Oscar sporadically for various live appearances.
I think there's a chance we might see him with Oscar at the Henson Company event next Spring. We'll just have to wait and see. So I don't think he's completely done with Big Bird and Oscar just yet. They're always going to be a big part of him. But we have we have Eric and Matt to fill in until then.
As for Matt. I don't really see why we can't complain about him. The character would be better served with another performer. It just doesn't feel like Big Bird the same way Eric's Oscar feels like Oscar or Stephanie's Prairie Dawn feels like Fran Brill's Prairie. It seems like a different character whereas even when Caroll did him for the Julia episode I could still see the same BB that asked about Mr. Hooper, ran away from the Dodo's, etc. I don't see any of that Big Bird in Matt's performance.
I know I felt the same way when Fran Brill retired, as well as Frank Oz (If Jim were still alive I'm sure he would be retired as well). But it's a different show now. It doesn't feel like a real neighborhood anymore. A neighborhood where muppets where just a small part of a community with real people that went through experiences like hurricanes, grief, adoption, etc. A place that you felt like you could visit and knock on Oscar's trash can and he'd be there. It feels too surreal, too trendy, too random. I miss the episodes that focused on a community at it's core. Not just a spot where a celebrity could play some random, one off, trendy, unrealistic character. The street itself has less of a presence. It feels like an empty shell of what it used to be.