I think Google prefers to support existing open source projects that are successful. Internally, a lot of Java engineers at Google use Eclipse, which is a great IDE for Java development. No need to re-invent the wheel, instead it makes more sense for them to contribute to the success of Eclipse.<p>FYI, Google also just donated $20K to the Eclipse foundation:
<a href="http://www.thepowerbase.com/2012/09/google-donates-20000-to-eclipse-foundation/" rel="nofollow">http://www.thepowerbase.com/2012/09/google-donates-20000-to-...</a>
Because you can already develop Android apps quickly and efficiently with a number of already built and well supported IDEs? It makes no sense to spend money on something for a niche thing like Android development.<p>Also <a href="http://developer.android.com/sdk/index.html" rel="nofollow">http://developer.android.com/sdk/index.html</a>