I don't believe that the American Revolutionary War would have been won without his aid. After all, he was the "cash cow".. So how come there isn't any credit for him?
It is certainly true that French aid was critical to the American war effort. More importantly, it France had not gone to war with Britain, the British would not have had to end their fight in order to focus on protecting more important (i.e. profitable) colonies.
That said, Louis XVI never really got much thanks for his assistance. There was some good will and thanks for the King. Louisville, Kentucky was named for him in 1778. But American leaders also understood that King Louis was not supporting the Revolution out of any sort of idealism. France wanted to tweek Britain for losing Canada to them a few years earlier. France also hoped to use the dispute to gain influence in America and perhaps take advantage of Britain's weakness to capture other colonies. In other words, while their goals happened to coincide, the King was only acting in his own self interest.
Another reason was that the Revolution became about democracy. There were many fears that King George of England would eventually be replaced by another King. Showing too much honor to another King might get an American accused of being a monarchist. Only a few years after the American Revolution, the French Revolution overthrew the King. Liberals in the US supported the revolutionaries against the King. Conservatives tended to support Britain over France by that time, so the King was left with little support in America.
Instead of honoring the King, Americans tended to focus their honor and gratitude on another Frenchman, the Marquis de Lafayette, who had come and fought as an officer in the Continental Army, and later lobbied France for more assistance. He was greatly admired by many of the men who ended up running the new US. So he tended to become the personification of French Aid rather than the King.
I hope this helps!