Answer: Because soccer has a bigger worldwide TV following than tennis. He plays for the Real Madrid of Spain and the games are transmitted across the globe to hundred of millions of fans a year. And when in July 15, the 2018 World Cup ends and Cristiano Ronaldo played with his national team of Portugal, more three and a half billion people would have watched the games or an average of 116,000,000 people every day. The income in TV ads alone will be amazing.
Tennis? Not even in their wettest dream they can achieve that. But Equal Pay is the buzz term lately because “Feminism.”