While Apple seems to think leasing their iCloud services and granting usage of their iOS operating system on your device is similar, they are not. There is one big difference between the two environments.
Apple iCloud is a set of services that runs in the cloud. It consists of software and hardware that is purchased and maintained by Apple.
Apple iOS is an operating system, which includes software software applications, that runs on Apple hardware. This hardware is purchased by a consumer. It is not leased. It is owned. The hardware hosts the iOS software.
As hardware owners, we should have the right to turn all features on and off with opt-in the default setting. It is, after all, using our hardware in a manner that impacts performance, storage, and battery life. It could also be impacting our privacy.
There needs to be a recognition by Apple that a local operating system and associated apps running on a local device is not the same mentality as running cloud services, even though the technical constructs may be the same.