This is not entirely correct. Google has no possibility to break things in short time if they work exactly like the Google implementation. Although Google can update their clients through automatic updates there are still devices only connected via low-bandwidth and similar things which will receive the update heavily delayed. And finally there are devices that will never receive certain update.
Example: The Android Market API (yes android market, the name it had before play store) is still available and can be used, although it was replaced by a Play Store API years ago and there exist public client libraries for using it and the API is heavily used to grab free apps from the play store. However, as Google Play was never available for Android < 2.3 and there are still some users with this OS, the only way to disable this old API would be to remove Play Store access for a few hundred thousand users, which they refused to do until now.