That isn't really figurative because that is saying exactly what it means. Figurative language is something that doesn't mean what it says. The phrase above means exactly what it says. In “Fame is a fickle food” the closest thing to figurative language is rhyming and that isn't figurative language. These poems are a great example of how you don't have to have figurative language for it to be a poem.
Lastly, they are different because in “ Fame is a fickle food ” there is variety of rhyming not every line but every few lines there is a rhyme for example “whose table table once a guest what not the second time is set”, that's a true rhyme. In the poem “Famous there is no rhyming. The beginning of each line begins almost the same. The blank is famous to the blank. For example “The river is famous to the fish”. There is no rhyming in “Famous” which means they are