Well, AirPods work with Android, though not with all of the features iPhone users get, and Apple Music is available on Android. I also would not be surprised if the Apple Watch is eventually offered for Android, provided Apple can get the security needed to store that kind of sensitive data on an Android phone. iTunes and the iPod eventually made their way to Windows, even though Apple long saw the iPod as a way to get people to buy Macs.
I see the Watch, AirPods, and services as ways for Apple to continue making money off customers in the years when they aren’t upgrading their iPhones, which is needed if people are buying iPhones less often. Getting a Watch is like upgrading your iPhone, providing new features and functionality, without having to replace an iPhone that you’re still happy with. My guess is that Apple’s main goal is to make money, and the mix of which products and services generate that money doesn’t matter as much as long as Apple hits its revenue and margin goals. And considering how few people switch from iOS to Android, I don’t think Apple is at much risk of losing iPhone customers. I think they’re happy to play the long game, and a dip in 4thquarter earnings that are ONLY the second best earnings of any company in the history of business is reason to panic or make a major strategy shift.