King Croesus

In Chapter 3, Vonnegut continues his excellent allusions, anecdotes, diction, etc. On page 61, though, he takes his mastery one step further. He is able to mix an allusion with a simile at the same time. How is this possible? Because he's Vonnegut, that's why.
The quote I'm referring to is found in the middle of page 61, when Vonnegut refers to the rich life of Billy Pilgrim. The quote is, "[Billy] was rich as Croesus, something he had never expected to be, not in a million years." My first reaction after reading this sentence was, "Who is Croesus??? And why did Vonnegut refer to him? That's a nice simile though."
Consequently, I turned to Wikipedia. Wikipedia also describes Croesus' life as a very rich one, lived in extreme luxury as he ruled as King of Lydia of ancient Greece. He is credited with producing the circulation of the first gold coins in history. He is also famous for forming an alliance with Sparta during the Greek struggle against Persian onslaught. (I also learned that his name is not pronounced "crow-sus" and instead "cree-sus". It certainly still looks like Crow-sus to me, so that's what I'll call him from now on.)
Obviously, Vonnegut had a purpose in naming Crow-sus while describing Pilgrim's optometric riches. Netting $60 grand a year must have something to do with it. He also owned a share of a Holiday Inn and 3 Tastee-Freeze stands. But how is that comprable to a King of Lydia? The answer is that it's just a simile, so it doesn't have to be entirely accurate, but make a point that, in this case, Billy is much richer than he ever imagined an optometrist could be. Billy is living a life of luxury, and he is similar to Crow-sus because they both exceeded the typical living standards of other people in their respective cities and times.
So, with Vonnegut's epic allusion/simile combo of referencing Crow-sus, he is able to enthrall the reader with a connection to the ancient past. He also gives further explanation to just how extremely luxurious Billy's life was becoming.