>>951861
Fast food is a tricky business. plankton and Krabs backstory makes it apparent that Fast, edible, good food is very difficult in-universe. The Kelp Shake episode also confirmed this. And as far as examples of other restaurants, we have Weenie Hut's and Goofy Goobers, which likely have some extreme social stigmas against them, or haute cuisine places, as evidenced by the Exchange episode.
Krabs has a complete monopoly on food that's both convenient and easy, so I imagine location doesn't matter so much as the fact that it exists at all.