I think one reason why they don't have Friday credits anymore is, not because there are technically no "Friday" episodes, but also, unfortunately, because the closing credits are so short, they can have them every day now. Because looking back, in its golden age, Sesame Street had just about the longest credit crawl I ever saw, and it was unique in the way that from 1984-1992, it was sort of made part of the street story, since they would come back after it to do the CTW announcement. And I have to say, the closing credits were always one of my favorite parts of Sesame Street. A lot of people don't even realize it, which explains the reason why a lot of Friday episodes I've come across in trades do not include the closing credits.