Selling Android isn't generating revenue, but that makes sense because Android is adware and also a platform. Google doesn't want to sell it directly and harm those revenue streams.

Many (most?) people primarily search from their phones now, so I imagine Android generates a lot of ad revenue. Android is even more important because most people don't know how to block ads on it, whereas desktop ad blocking has become mainstream.

Google Toolbar, Chrome and Android: all of these were created with the goal to increase the number of searches. If Android wouldn't have been created, Apple could ask as much revenue sharing from Google as they want and slowly destroy Google in the process.

Oracle seems to disagree:

http://www.businessinsider.com/oracle-google-generated-42-bi...

But while we can't take Oracle's statements at face value, how do you know Android isn't making Google money? It's also likely that without Android, Google's revenues would've declined a lot faster.

Even if say people would've still used Adsense/Admob on iOS or other mobile operating systems, look what Apple did - it allowed adblockers on its platform. Google doesn't allow them and Chrome, which is the dominant browser on Android doesn't support extensions, so no adblock there either.

there are adblocks on google play store.

its just that the mobile chrome doesnt support extensions. google isnt stopping anyone from a local "adblock" proxy or editing the phones host file.