Apple's Services revenue hit 10 billion per quarter in the last earnings report, and it's growing steadily. Yeah, it doesn't compare to hardware sales, but I don't think it can be called a minor insignificant stream any more, can it?
The closest might be recommendation systems, but afaik even Netflix only collects from its own information pools, and the main chunk of it is probably for their custom shows; Amazon definitely doesn't track that much data about their users, because their recommendation system might actually be useful if it did.
[1] https://en.wikipedia.org/wiki/Category:Apple_Inc._services
Also keeping an internal profile of registered user is very different from squeezing every cent of advertising out all available user data
Not sure how it works, but whatever I see on Amazon shows up as ads on Facebook.