You're right. JBQ quit because of the reasons you mention. But he was tired of AOSP in general and doubted the intentions of powers that be. Android was notorious for its non-cooperation with the rest of Google (remember the android browser vs chrome wars?), IIRC. Removal of Andy Rubin from the Android division was a sign enough... Ever since Sundar Pichai has taken over, Google has continued to close source a lot of code that was earlier part of AOSP.

http://arstechnica.com/gadgets/2014/11/android-5-0-lollipop-...