Yes and no. There's some dirty politics here. Getting a company like Amazon to take Android and use it for their own devices was a huge benefit to a growing Android in the face of iPhone's massive market share. Now that Android has a firm footing, Google sees Amazon not as an ally, but a competitor. So, in order to compete with Amazon, Google has been silently pouring more functionality into their proprietary, closed source play services. The open source part of Android alone is actually rather bare bones, forcing Amazon to implement redundant (also closed source) features to bring parity to their own devices.
Meanwhile, Google has also added to their SDK a number of hooks that make the lives of developers easier, but if you use them the closed source play services are a required dependency for your app to run... Android's fragmentation problem is not just for OS versions, but increasingly the OS is growing fragmented between different OEMs! Such a mess.