It was never theirs to give away.
Android was built on Open Source software. For the most part, Google couldn't make it theirs. However, that didn't stop them doing everything in their power to lock it down and shut out other people, all the while touting how Not Evil they were and using Open Source as a marketing point.
Google engineers have given a lot back. But in other ways the company itself as pulled some VERY sneaky moves to lock out others from Android. The following is a very good read on the subject.
https://arstechnica.com/gadgets/2018/07/googles-iron-grip-on-android-controlling-open-source-by-any-means-necessary/
Biting the hand that feeds IT
