Microsoft's apps are specifically an example I've given of how closed Android truly is: Even Google's competitors, which have all of the same service capabilities, are essentially forced to use Google Play Services. Especially when you consider the other top HN item today about how Google now essentially requires all apps use a closed source Firebase library for push notifications.

And while yes, Google Location Services is a location provider that slots into Android, you are missing that Google has convinced app developers to call it directly, rather than using the Android location provider. This means that no alternate location provider will do: Google Location Services is hard coded into almost every location-based Android app today.