Google is incompetent at expanding into adjacent markets to search engine marketing. That is their core competency. You think they can enter the automobile industry? You're insane.
Who says they need to "enter the automobile industry?" They just need to license their tech. Also, nobody else is going to be able to do it anytime soon without their data. The cars rely upon the street-level map data Google has, and nobody has as it or is any position to get it anytime soon.
That's why they failed at building a mobile operative system. Same happened when they tried to get into the email business. Or the office applications sector.
So this is a nice long list of reasons to "go long GOOG"? Let's add up the billyuns they've made in:
Mobile operating system: we'll get back to you on that
Email business: brand investment!
Office applications: Literally hundreds of satisfied paying customers, a few even break into 3 digit employee counts. Coming to offline any decade now.
Web browsers: the tracking data is worth a hundred times what we paid for in commercials and r&d.
