This is a lot of apples and oranges and limes.
I've had an Apple iTunes account for more than six years, going back to when I first got an Video iPod and a first gen Macbook Pro. During that time, I've spent, maybe, $10 on songs and nothing at all in the app store. My old MPB is barely functional and now sits in a corner, turned off. Can't run the modern OS, too slow, too hot, tiny RAM. Not even worth ebaying.
The iPod mainly gets used with a matching ancient iTalk gadget to record meetings. That's it. Apple is making nothing from me but they have an account. Woo. Go ahead and count that. Believe for a moment it means something.
Facebook does not have a card on file. Users at FB aren't the customer anyway. They are the product. The advertisers are the customer at FB. They pay. The product does not pay.
Anyhow, I get most of my music from Amazon. It interfaces nicely with iTunes, which barely gets used, quite honestly. But I spend FAR more with Amazon on actual, physical products. Amazon gets more of my dollar than Costco, Walmart, Harbor Freight, Home Depot and a ton of other retailers. If we want to compare retail operations, there's a limit to what Apple can physically sell to someone. A handful of their own products and perhaps whatever One can find in an Apple store. Such is not the case with Amazon. It's hard to find something they don't have, even if the price is not always the best. I've got Prime but no time in the world to watch any videos so for me, that matters not at all. Just send me my stuff fast.
Google would be next. They're getting my app money. Play Music is finally starting to work well. They're trying to figure out the retail side -though I wish they'd quit fooling around and focus on doing what they do best. All these consultants trying to plot the future just end up wasting OPM and time.