I think when you accomplish some of the things Google does, it becomes less of a "advertising company which enjoys masquerading as a computer science R&D lab" and more of "an advertising company that owns and funds a computer science and engineering R&D lab".
Advertising is where they make their money. It is nice that they do cool things, but few of those things have anything to do with their core business.
My point was that they do a lot of fun things that aren't core to their business. Properly filing their SEC documents might be worth a little more attention. Not quite as sexy as self-driving cars, but if they can't keep the core business running then they won't have time for autonomous cars.
update: confirmed by R.R. Donnelley & Sons