During the Roaring Twenties, the setting of F. Scott Fitzgerald's novel, speakeasies grew out of Prohibition. These speakeasies were establishments that served alcoholic beverages illegally. Because liquor was prohibited in the United States, criminals made fortunes smuggling from Canada. Then, as an outgrowth of the burgeoning of organized crime, prostitution and gambling became huge businesses. In Bret Harte's short story, the Duchess and Moher Shipton are prostitutes and John Oakhurst is a gambler, who easily could have prospered in the 1920s of Fitzgerald's era.
Of course, a rascal such as Uncle Billy, the sluice robber and the thief of the mules who leaves the others stranded, has many parallels in the setting of The Great Gatsby. Meyer Wolfscheim is an unconscionable sort who makes cufflinks from a man's molars, an indication that he has no feeling for anyone. After Jay Gatsby dies, Wolscheim selfishly stays away, concerned for his own safety.