“If you’re so smart, why aren’t you rich?”

“If you’re so smart, why aren’t you rich?” (or, “If you’re so smart, why ain’t you rich?”) is a phrase sometimes heard in New York City, the nation’s financial capital. The Southern writer Eudora Welty used the phrase in a 1941 story, but she didn’t coin it.
 
The phrase dates in print to at least 1927 and possibly emerged from vaudeville. There are several variants for he second part of the phrase, including: “If you’re so smart, why ain’t you President?”
 
   
Wikiquote: Eudora Welty
Eudora Welty (April 13, 1909 – July 23, 2001) was born in Jackson, Mississippi, United States.During the 1930s, Welty worked as a photographer for the Works Progress Administration.
Sourced
If you’re so smart, why ain’t you rich?
“Petrified Man”, 1941
           
20 July 1927, Emmetsburg (Iowa) Democrat, pg. 3, col. 3 comic illustration of hobo:
IF YOU’RE SO DARN SMART, WHY AIN’T YOU RICH?—READ EVERYTHING ON THIS PAGE AND NEXT WEEK RIGHT HERE I’LL TELL YOU HOW TO BE “THE RICHEST MAN IN TOWN”
   
4 January 1932, Oil City (PA) Derrick, “Why ain’t you rich?,” pg. 6, col. 2:
“If you’re so darn smart why ain’t you rich?” is one of the latest vernacular phrases being bandied about. But the average mortal can’t be smart, not too smart, for he is worth only 94 cents, according to a noted medical authority.
 
7 January 1938, Abilene (TX) Reporter-News, pg. 5, col. 7:
The collector often thinks of, but can’t repeat the old adage, “If you’re so darn smart, why aren’t you rich?”
 
Google Books
Black & White
Published by Greenwood Reprint Corp.
1939
Item notes: v.1-2 1939-1940
Pg. ?
You probably need a little of that, yourself; because if you’re so smart why ain’t you President?
   
27 April 1940, Mansfield (OH) News-Journal Toots and Casper comic, pg. 7:
NO WONDER! HE AND I BOTH GOT THE SAME THOUGHT, CASPER…IF YOU’RE SO SMART WHY AREN’T YOU PRESIDENT—?
 
Google Books
W. Somerset Maugham’s Introduction to Modern English and American Literature
By William Somerset Maugham
Published by The New Home Library
1943
Pg. 13:
Billy Boy stomped through the group of wild-haired ladies and went out the door, but flung back the words, “If you’re so smart, why ain’t you rich?
       
23 April 1946, New York (NY) Times, pg. 2 ad:
After reading your last “smart alecky” letter I was tempted to ask you, quote, “If you’re so smart, why ain’t you rich?”, unquote.
 
21 September 1947, New York (NY) Times, “People Who Read and Write,” pg. BR8:
Mr. Powers thinks that Eudora Welty’s line: “If you’re so smart why ain’t you rich?” sums up our stage of civilization.
 
Google Books
The Reporter
By Max Ascoli
Published by Reporter
1954
... of affection and of friendly jest, of whom it is irreverently said that he has reversed the old Texas gag from “If you’re so smart, why ain’t you rich?” to “If he’s so rich, why ain’t he smart?”
   
13 January 1955, Coshocton (OH) Tribune, pg. 21 comic:
(Student addressing his teacher—ed.)
“IF YOU’RE SO SMART, WHY AREN’T YOU PRINCIPAL?”
   
8 December 1957, New York (NY) Times, “Notes on KP and/or The Egghead; An ‘aging veteran’ ponders our national attitude toward brains” by Bill Mauldin, pg. SM37:
ONE of the hoariest bits of repartee in our lexicon is still popular among schoolboys: “If you re so smart, why ain’t you rich?”
     
18 July 1965, Chicago (IL) Tribune, pg. J9:
If You’re So Smart, Why Aren’t You Rich?