What I'm saying is, if there can be equal prize money at some events, why not for all events?
Don't you care about equality?
At a certain level of abstraction equality can seem an attractive notion, but the devil is in the detail.
The winner of any tennis match gets far more than the loser, financially and in terms of prestige, what would make it more equal is if every match had the same amount of money and prestige, but in order to achieve that, you literally undermine the very idea of sport - which is inequality.
Men's tennis attracts more than women's, women's attracts more than wheelchair tennis, which attracts more than amateur, and so on. Great players tend to attract more than those who aren't so great, really great players get the lions share of money and attention.
And you can't make tennis equal - even in terms of participation, if you're a man who is 5'2", and old, it's unlikely you'll ever be great, our biology makes it an unfair fight right from the start. Even if you did try to rig the sport so men and equal get equal prize money, most of us can never get that prize money because the cards were stacked against us in the form of biology.
There's a science fiction short story by Kurt Vonnegut called Harrison Bergeron about a society that tries to make everything equal - those who have skills, who are beautiful, intelligent, funny etc, are handicapped so everyone is the same, but it's a dystopian society for that very reason.