Anyone who says this or its many variants has no business acumen or creativity. It is the banal banter of the boring. This sounds harsh, but seriously it grows tiring watching people desperately try to stretch everything to fit some nonsensical hypothesis.
Google is a very large company and their product is technology. They happen to have entered the market at a time when advertising was literally the only way to make money online (they originally tried to use the web purely to sell business search appliances, but that didn't pan out), but assuming that their entire future business model is ads is the domain of simpletons.
And, as an aside, I see more ads on my iPad and iPod Touch than I do on my Nexus 5. Isn't that weird?