If they want to know what I ordered from iTunes and Amazon that much, go ahead..
Oh Grasshopper! How wrong you are! It's that attitude that Google and others want to encourage. But as my relative who works in this area would explain to you there is much more than that they are gleaming and storing about you. In the future, folks will really regret that they gave Google and others, e.g., Facebook, all of their photos, all of their personal and business contacts, every email and message they wrote and received, everything you ever purchased, where they drive, who they visit, what they read and watch, what they search for, everything about their families and friends, etc.
That information is being assembled, stored, sold and stolen because it has value to advertisers, foreign countries, law enforcement, intelligence agencies, criminals and, depending on where you live now and in the future, totalitarian and/or evil governments.
Apple's focus on privacy is slowing this down for those who use its eco system, but can't stop all the leaks, e.g., when you use Google search, they have that forever for law enforcement, hackers, etc.
BTW, this website, MR, has a minimum of 15 trackers being loaded on your device as you read this.