Betting on the mobile OS seems old fashion to me. In a few years we'll have complete parity in mobile. It really won't matter what OS you use. Even today we're pretty much there. I don't think Android can Windows-ize SmartPhones. There's too much competition and already too much parity. Google has a big problem if people are buying Android devices to mostly spend their time in non-Google services with non-Google ads. They'll still have a lot of mobile advertising but it may not be in the same ballpark as more targeted ads closer to the services/apps people are sharing data with.
Over the next 5 years which is going to be more valuable: leading in social apps or mobile OS (with Android)?
I don't know the answer to that question, but it seems like Google is placing their bet on mobile OS.
Which do you think is more valuable...the OS or the social apps?