contract. And there are two pots of money; For exhibition games, The Men's pay is actually incentive based, while the Women get a flat salary. Men get paid per game and more money for victory. This is based on their CBA.
Then there is the FIFA world Cup payout, which is incentive based for both and where the greater divide is. The difference is the men get way more from FIFA for even making the World Cup than the women get for winning it. And, that is because the Men's World Cup generates way more money than the Women's World Cup.
It's not as simple as saying we'll give them the same salary regardless of gender.