The Francis Scott Key song, though written in 1814, was not fully recognized as the American national anthem until patriotic fervor struck upon involvement in World War I in 1917. The Star-Spangled Banner would not be officially declared as the American national anthem until 1931, and would not even be played at a sports game for the first time until 1918.
As this article notes: “No theater audiences stood while it was being played in 1898, and, in fact, the general disposition at that period, at least in the Northeastern part of the United States, was to elevate ‘My Country, ‘Tis of Thee,’ to the place of honor.”
I can personally attest that being the singer for the national anthem before a sports game, as this column I wrote for my college newspaper years ago recounts:
‘The Star-Spangled Banner’ as Nation’s Anthem: Only Since the Present War Against Germany Began Has It Been Generally Recognized — The Real Story of Its Origin
From Sunday, July 15, 1917