I give nothing but credit for Spongebob in trying to reference the old school hosted kid's show. Simpsons basically was grandfathered in with Krusty the Klown, and that character is specifically created by Matt Groening who not only grew up watching those sort of shows but once gave a detailed autobiographical piece in a Simpsons comic about how he was on one once. heck, when The Simpsons started, most of the audience knew what a locally hosted kid's show was.
Spongebob came out in 1999. I don't know exactly which was the first episode that used Patchy the Pirate, but it was early enough on. Kids really don't know what a locally hosted kid's show is. They didn't know it then, they sure as heck don't know what one is now. Spongebob's got some sort of popularity immunity or something. I guess kids that don't get it just think it's a funny bit or something.