Well, right. Thats my point. They have enough parts in "Android" which don't fall under GPL and thus they can keep them proprietary.
I think "there isn't enough software under the GPL" is not a criticism of the GPL's effectiveness. If anything it supports the GPL as a method for ensuring user freedom.
This isn't about not wanting to "give back" to the community, companies using permissive licensed software are contributing back. It is about that the GPL is incompatible with the business model of all companies which are licensing (selling) the software they produce.