Ask HN: Why did Google create and invest in Android?

How does it make money off Android and how is the investment justified? The popular analogy is its the Windows of the smartphone world. Not quite true because Windows gets money from partners. Android is free. They have to rely on ads and app purchases. Google services are immensely popular (and very good) and if they create apps for other operating systems (like maps, voice, voice assistant etc) most people would definitely use them giving them ad footprint. Also their admod could be built into every app irrespective of the OS. So their share of ad revenue is not going to be dented. So what would Google lose if say Android did not exist today? I know they got into hardware now but that is not their plan to begin with. I know I am definitely not seeing something, What am I missing here?