[microtonal]

Do they actually have a good way to monetize android

As far as I understand, the initial motivation is to avoid being locked out. Suppose that iOS held 80% of the market, they could change the default engine, replace Google Maps with Apple Maps (like they did), etc. Given that smartphones and tablets are now commonly used to access the web, Google could have lost a serious chunk of traffic.

In other words, Google does not have to monetize Android directly, it exists to keep people in Google's ecosystem.