Pretty rich and famous for athletes "no one gives a shit about."
LOL, that just proves my point; we must stand them because they're humans like us. We can't put them in cage and take out only for fuking and cooking!
We give them little bit something and they feel important.
Plus of course other females follow them... that's why female athletes get even little tv-time! But no one of us important humans, men, follow female sports. As long as we're hetero that is. And that's what counts.
update: Other women may buy shoes that Williams for example advertises - that's why some female athletes have contracts. Nothing to do with them being watched by hundreds of millions of peoples when they try to play tennis.
Just like with children!
No matter how awful it is to watch some stupid pony riding We don't tell them 'you suck, go home'. Instead we act along and make them feel good.