It's already happened implicitly with the rise & spread of the "technical interview". By rote memorization of a body of knowledge which may or may not be applicable to the job at hand. Given the interchange between employers, these are more alike than different. Why would further formalization be any more valuable than say the Interior Decorator exam and license in Florida?
Why do you assume that programming is more like Interior Decorators than not more like Civil Engineering? There's been a number of cases in our history where software has killed people or cost people/corporations millions of dollars.