https://www.tbray.org/ongoing/When/202x/2020/02/09/Why-Android
Vic Gundara, the then-VP at Google on being asked why is Google doing Android:
“The iPhone is really good. The way things are going,Apple’s going to have a monopoly on Internet-capable mobile devices. That means they’ll be the gatekeepers for everything, including advertising, saying who can and can’t, setting prices, taking a cut. That’s an existential threat to Google. Android doesn’t have to win, to win. It just has to get enough market so there’s a diverse and competitive mobile-advertising market.”