The biggest difference I've noticed is that the newer episodes are targeted to a younger demographic, which makes it seem very dumbed-down compared to the old stuff, but it means younger kids can keep up and learn from it. My 3yo learns a ton from the recent episodes, whereas the older sesame streets are just a little too complex for her to follow. I'll try the older ones on her once she ages out of the recent ones.
Hi Bonnie, so sorry to be randomly commenting on this post, but I can't comment on one you posted in 2019 that I'm interested in (about BBS). I'm a journalist researching the topic. My email is in my bio. Thanks!