I seriously doubt we have to worry about Sesame Street. right now. We've seen how supportive people like Barack and Michelle Obama are to the show. Elmo's popularity is also what keeps the show going. Because he is the youngest character, he hits the target audience's level that Sesame Workshop is pushing for.
(Oh and for all of you Big Bird fans like me, don't worry about him. Carole-Lynn Parente stated that despite the littel red guy's popularity, he is still an iconic figure on the show. You've seen how both he and Caroll get the same amount of recognition as Kevin and Elmo)