Specific? An entire generation is specific? Not just my generation either. I bet you the over 55 crowd would not know what it is. Yes, we all know what Spongebob is and what he looks like, but to know the food in the cartoon, that is too detailed for the general person who has never seen the show to know.
Simpson's is the same way. But the difference is that a Krusty burger is gonna be a burger. So when you walk in and look at all the storefronts, you know you are getting Italian at one, burgers at another, etc. But until someone looks at the menu they would have no clue what was served there and too many people would think it is seafood unless they had watches Spongebob.