because Silicon Valley is in California, it's supposed to be the world's hub of tech leaders. If we have a candidate pool that is so poorly educated it doesn't bode well for sustaining that technology lead.
Palo Alto has one of the highest levels of education in the country. The rest of the bay area ranks highly as well. However that entire region only makes up less than 20% of California's population. The rest of the state brings down the average.