“Indecision is the key to flexibility”

“Indecision is the key to flexibiity” (less often given as “Flexibility is the key to indecision”) has been featured on gift items such as T-shirts. The saying humorously celebrates the indecisive.
 
“The key to flexibility is indecision” has been cited in print since at least 1975, when it was recorded as a graffito at Yale University. 

       
Google Books
The Reader’s Digest
Volume 107
1975
Pg. 113:
Yale University: “The key to flexibility is indecision.”
 
15 March 1976, Berkshire Eagle (Pitttsfield, MA), pg. 18, col. 7:
Lighter Side
Up against the wall
Graffiti flourishes on campuses, for example at Yale: “The key to flexibility is indecision.”
—“The Thinking Man’s Graffiti” by Timothy Yu and Jonathan Jang (Timco).
 
30 May 1976, Seattle (WA) Daily Times, “Odd Parcels” by Alf Collins, pg. D2, col. 1:
The graffito of the month from the newsletter of the Washington Section of the American Institute of Planners:
 
“Indecision is the key to flexibility.”
 
Google Books
Designing and Delivering Cost-Effective Training and Measuring the Results
By Ron Zemke, Linda Standke and Philip Jones
Minneapolis, MN: Training Magazine
1981
Pg. 225:
A decision maker who didn’t like to make decisions until the last moment (or after it) confronted us with this one: “Indecision is the key to flexibility.” No one could defy logic as simplistic as that. If you don’t make any decisions, you have left all your options open.
 
Google News Archive
3 July 1981, Montreal (Quebec) Gazette, “Time for Murphy to stumble again” by Nick Auf der Maur, pg. 3, col. 5:
Indecision is the key to flexibility.
 
17 February 1982, Tyrone (PA) Daily Herald, pg. 13, col. 2:
BIG PROBLEM
Many so-called executives firmly believe that indecision is the key to flexibility.
 
Google Books
Murphy’s Law:
26th Anniversary Edition
By Arthur Bloch
New York. NY: Perigee
2003
Pg 37:
Schroeder’s Law
Indecision is the basis for flexibility.
(...)
Mullins’s Observation
Indecision is the key to flexibility.
   
Google Books
The Routledge Book of World Proverbs
By Jon R. Stone
London: Taylor & Francis
2006
Pg. 231:
Indecision is the key to flexibility. (French)