This isn't generally true at all. Ella Fitzgerald has been "the First Lady of Song" since forever, various women have been called the First Lady of rock, pop, t

This isn't generally true at all. Ella Fitzgerald has been "the First Lady of Song" since forever, various women have been called the First Lady of rock, pop, this or that sport, etc. In general I think I've only heard "First Lady of X" refer to a spouse when X is a country. In any other case it's always somebody famous in their own right.