Firstly, the car companies have been shipping for the last few years many of the key systems of an autonomous car. Even some of the cheapest cars can self park and auto brake in the event of an impending collision. Adding more sensors and better control systems builds on this.

Secondly, nobody knows who is leading the industry. But we know it's not Google since all of the car manufacturers have their own programs in fairly advanced stages. And due to the consolidated nature of the industry key technologies are shared within the groups. So if Google has no one interested in their technologies and they don't make cars then how will they ever lead anything ?