Why does it matter, the source of the income? If each team is generating approximately the same revenue in sum total, why should the players not be receiving equivalent amounts of money to take home to their families?
Again, you are mixing things up.
World Cup prize money =!= total annual income of football players
Each player, male or female, gets a fixed % of the total prize money pool allocated by FIFA.
The pool in the men's WC 2018 was ca. 400m€, in the women's WC 2019 it's 30m€.
While the US men team might not be responsible for it, they happen to play in a tournament that generates more revenue overall.
Why Hyundai, Budweiser, McDonalds, Adidas, the TV networks pay so much more money to the men's WC instead of the women's WC is a whole different topic.
What really rubs me the wrong way, is that FIFA allowed the Gold Cup and Copa America finals to be played on the same day, taking away attention from the Women's final.