Can you really expect any different from a company founded from within the halls of Stanford, and then staffed primarily from there?
On the other hand, I bet if you sat down and ran the numbers, recruiting from state schools isn't productive. For better or worse, school selectivity is tied with rankings -- for every Anthony topping the charts of state school is a graduating class of Anthonys at the elite schools. Cherry picking your one Anthony per school is likely harder than showing up to Stanford where they picked cherries 4 years ago.
Moreover, Google recruiters are likely already flooded with new grad applicants from non-elite schools, while every year GoogFaceAmaple is pushing forward their recruiting funnel earlier than the competition. Eventually, I imagine they'll simply interview candidates the summer between receiving their college acceptance letter and fall semester freshman year.