You are talking about a sport where the winner receives a tremendous amount of money, and the networks get a lof of money too. Tennis is not where it used to be either, as at the moment, there are very few major big stars from the US on the men's team.
Equality is great, but if the men's prize money is not increased, other championships will eventually surpasse it, and perhaps some of the top players might bypass it. The question is will advertisers pay as much for a women's early match compared to the men's early matches?
Pro Basketball, pro soccer, and many others are still vastly different, as it really depends where the money comes in from.
If you are a promoter, and you know 80% of your money comes from the men's side, and 20% come from the women's side, would you still generate 50% money for both. It sounds good if you can cover the expense, and have enough money coming in, but if you don't, you either choose one, or work on it.