Whilst the wisdom of a proverb remains constant, its examples change. This is true not only of the centuries-old saw, but even those coined within our lifetimes. "The opera isn't over till the fat lady sings" began life in the press box of a rodeo at Austin, Texas in 1975 as "The rodeo isn't over till the bull riders ride".
"The Proverbial Word,"
Word Ways: Vol. 26
, Article 15.
Available at: http://digitalcommons.butler.edu/wordways/vol26/iss2/15