For the same reason:
a red hot maria can be double bagelled by a lindsay,
kim can win every title under the sky except the one that counts the most,
amelie can barely win games against kim,
serena wins a slam one minute and gets bagelled the next,
that players like mashona washington have a win over sharapova yet venus doesn't,
tennis is all about match ups, be on when you need to be on the most.
But to try and answer your question, kim's game will win anyday against most players coz she is a brick wall and has an amazing defence game, she struggles against very offensive player with good defense like venus serena and justine.
I dare say shd will struggle against maria to, maria has both!
Rena- a tennis great! 22 at striking distance.