Nope, you can't pay them the same - at least not now. They might be able to paid the same in a Utopian future where women generate the same revenue from commercials and merchandise as men. But until then soccer clubs can pay them a living wage. As any company does: you pay a person with the belief they will generate more revenue than you pay in wages. If at the end of the year/a few years they don't, they get fired.