Apple’s careers page has job listings indicating they are using an industry standard data warehousing, ETL, star schema etc. user analytics stack for something. I don’t think any specific claims they made about privacy are false (they have many different products and services), but they are definitely doing some kind of data mining.
Whenever you install/update iOS/OSX they specifically ask you if you want to send anonymised data to Apple which details how you are using the OS. They couldn't be more upfront and clear about it.
And when I was working at Apple years ago they were using a very old and clunky SAP system for all of their customer purchases. It would be pretty common sense to ETL this to a data lake in order to do reports e.g. which apps are popular.
