It boils down to a race of money vs money, and the car manufacturers have taken together more money than silicon valley. Yes, silicon valley has boatloads of money, and even more insight into and control over our lives and data, but they can't deploy as much resources as the car industry can.
Silicon valley is a place that (mostly) lives off disrupting other industries and markets, and many of them are very vigilently fighting digitalisation. Just take Uber vs taxi companies. Or airbnb vs hotels. Or whatsapp vs mobile carriers (everyone remember having to pay for single SMS messages?). Or google vs libraries (that was the place you visited to research about a subject in the old days). Sometimes though the industry that's about to be disrupted sees that in the long run, it will lose, and I think the car companies have chosen to innovate themselves.
Silicon valley find other industries to disrupt though, they are very important.