This. I was born the year that the Sesame Street premiered and it was part of my morning toddler routine in the early 1970s. Watching the show with my daughter in the 1990s, I noticed Elmo's presence transmogrify from just another Muppet character to having his own segment. As his airtime expanded, that scratchy, helium-stricken voice could no longer be borne by my sensitive ears. To me, that was the death knell for Sesame Street. Kudos to Mr. Rogers for not giving Henrietta Pussycat her own segment ("Meow meow I'm da meow meow bomb meow meow").
Elmo is an interesting study in the evolution of Sesame Street for many reasons. Big Bird was created to be the avatar of the children watching, and there is an interesting generational shift around the show as Big Bird become such a symbol of the establishment that children stopped seeing themselves in Big Bird and a new "child advocate" niche opened up for Elmo to fill. For Mr. Spinney, getting a puppet into that role was an intentional design choice, and for Mr. Clash getting a puppet into that role was a lightning-in-a-bottle lucky moment in the zeitgeist shift and creative renewal of the show. Arguably the show would not have survived if it didn't showcase Elmo as it did, given whatever that generation shift was that happened.
I would hope that there are entire Anthropology and Sociology graduate theses devoted to that shift, because it is fascinating to this lay observer.
My son got hooked on the 80s versions that were/are on Netflix a few years ago.