What you're not seeing is the fact that GOOGLE make money mainly through ADs! They're first and foremost a search engine that get money via ads! If there are tons of these mobile computer aka smart phone out there than there are computer. The future gotta be smart phones. They're not going to wait and lose the market and let someone else dominate it. Microsoft lost the search engine market cause they were still OS oriented and google ended up capitalizing it and now dominate it. Google isn't going to sit back and let Apple do the same thing with smart phone. That's just foolish.
I think they also want to branch out to hardware to be like Apple. Or at least try to innovate and find new market, like the google glasses and such.
Microsoft had an advantage by shipping IE with Windows and making it the default browser. With a closed system like iOS, they have just removed Netscape/Firefox/Wikipedia/Google/Adobe Reader from the platform. And nobody could complain, because they all agreed that this is OK when they submitted their apps.
So if a closed platform wins the current smartphone war, the platform owner could just "turn off Google" at will.
Android can be explained in the same manner. Google saw the traffic potential the mobile web had, and they wanted to make sure they were the search engine of choice. The best way to do this is to control the software people use to access that mobile web.
I don't know if I would reduce the self-driving car to just increasing time to see ads though. Its much grander and in fact revolutionary than that.
Before Android and Chromebook, the masses all accessed Google's services through competitors.
A Blackberry is a piece of hardware.