But Apple hasn't ever been quite as exclusive as they're painted to be when it comes to peripherals and services. They've had iTunes on Windows for a very long time (yes, it's kind of a trash fire, but it's still there), and that was mostly to support the iPod. They have iCloud for Windows. Apple Music has an Android app, is supported by Sonos and Amazon Alexa, and even has a web-based API (no official "cloud player," but there's an open source one out there which Apple knows about and is apparently okay with as long as it doesn't use the word "Apple" in its name). And, of course, a lot of non-Apple products can receive AirPlay, and they appear to have gotten fairly aggressive in the last few months at moving AirPlay 2 into the third-party market.

So, Apple Services have been on third-party devices for years; they've just historically been a lot less enthusiastic about it than companies like Spotify and Amazon have been. I would expect to see them be way more enthusiastic from here on.