Prize money inequality has been a hot topic for a very long time as players have pushed towards having equal prize money between men and women in tennis.
To be completely fair, it's totally deserved. Men and women should have equal prize money for doing the same thing however the reality of the situation isn't so simple. Most of the prize money allocation comes from the revenue of the event itself and that comes from how many people watch the event.
If you tuned into the WTA Finals last year you could have seen extremely empty stands as WTA tennis simply doesn't generate enough buzz and interest as ATP tennis. It's the same across most sports because generally, the product is not as good as that of male counterparts. So it's a complicated situation which puts events in danger of handing out equal prize money but then operating at a net loss.
As with any business, that's not going to happen. In order to try and address that, the WTA has been secretly funding the endeavour. According to reports the organisation has pumped an additional 32 million into the sport to help events hand out equal prize money. We've had equal prize money at grand slams but now we've seen Masters events stepping up to deliver on the promise itself.
That's about as good as you can get if you're the WTA as you probably won't see that from the smaller events. It makes no sense for them unless they start to earn a lot more revenue. For now, this seems like a very good compromise on helping the situation move forward but it's something that's likely never going to get resolved.
The interest is simply not there whcih means the revenue is not there which means that there won't be any equal prize money.