Apple seems to be plateauing in terms of revenue, and although google's revenue is still growing I'm wondering how long it can last. There is only so much advertising that they can squeeze out of the internet. If you look at youtube, they have been putting in more and more ads in the last year which has helped boost revenue, but now there is nowhere left to go.
As for their non-advert products: how big a market is the thermostat market, and what are the chances that Google will somehow screw up Nest? Google isn't exactly very good at customer service, and you need that for hardware.
As for these amazing robots, we've been hearing for 50 years about how robots are going to be making our lives easier at home, but it hasn't happened yet.
As has been expressed at various places on the web, the Nest acquisition was most likely about more than just thermostats and smoke detectors. It was probably about good consumer product design in general.
No, it's simple: Google is not payed by people for search. They are payed to display ads, whether it is alongside search, or as part of AdWords.
Seriously, are you really arguing that Google's revenues are not primarily from ad revenue? With the sale of Motorola, it'll be back above 90%—just like it was before Motorola.
Despite a million products, they're still a one-hit-wonder in terms of revenue.