Android isn't truly open though. Sure, the AOSP is. However, before Gingerbread there were still a lot of advantages reserved for those who entered a commercial

Android isn't truly open though. Sure, the AOSP is. However, before Gingerbread there were still a lot of advantages reserved for those who entered a commercial relationship - for instance, access to the Google Apps (mail, calendar, chrome). Post-Gingerbread, Google has put the vast majority of their development into the Google Play APIs, which are not open and are only available to partners. This means that use of things like chromecast (for instance) are restricted to apps distributed through the Play store, and handsets running partner builds of Android.