Sure, but they count on it for significant revenue. If Google didn't want to pay it, but they kept Google, they'd be giving up that revenue from some other potential provider.
(Of course, if Google didn't want to pay it, it might cause a crash in the 'market value' of such a placement anyway).
(Of course, if Google didn't want to pay it, it might cause a crash in the 'market value' of such a placement anyway).