Yes, I'm sure Google has analyzed this. I'm just saying it's fairly surprising considering that $3 billion hinges entirely on the assumption that people won't change the default. Apparently there are approximately 700 million active iPhones in the world [1], so Google is willing to bet $4 per user on that assumption. I'm not saying it's a bad assumption.

[1] http://www.siliconbeat.com/2017/03/06/many-iphones-use-analy...