A common monetization method used by malware distributors is to secretly replace legitimate ads that get loaded on the machine (such as Google's) with their own.
Doing this on every single web page visited by that machine for the rest of its existence, and multiplying that by hundreds of thousands of other infected machines out there, and multiplying THAT by the dozens of different black hat groups doing this simultaneously, it adds up to a lot of lost money for Google.
To me it feels like they're throwing their competitors under the bus in this way as opposed to running slander campaigns or witty commercials like Samsung, Microsoft, and Apple do. I'm not saying this is their intention but that is the way it comes off and it cannot be good for their reputation.
A non-profit organization funded by the entire tech industry would have more credibility.
They do offer a bug bounty for their own products, to encourage third parties to do to them exactly what they're doing to Apple and Microsoft.
Of course, it's an uphill battle with the manufacturers/carriers. But as long as Google is not applying fixes to Jelly Bean, the manufacturers can always blame Google.
[1] http://www.androidpolice.com/2015/01/23/google-issues-offici...
[2] https://developer.android.com/about/dashboards/index.html