Jeopardy final clue on a patent stumps all three

The final clue on Jeopardy on October 18, 2011:

His 1922 New York Times obituary mentions that his patent no. 174,465 "has been called the most valuable patent ever issued."

Note that Thomas Edison died in 1931.

None of the three contestants got it right, AND the game ended in two-way tie. One contestant did guess Edison; another guessed Morse; the third was further off.