Apple limited data from being transferred between apps. So you can’t measure whether your ad being clicked in one app resulted in a purchase in another app (aka. a “conversion”). That throws a big wrench into ad pricing, because the sellers want to pay-per-conversion. It hurt companies like Snap, Shopify. Since Amazon owns both the search/discovery and checkout in the same app, this doesn’t affect them.
Also, Apple didn’t limit their own advertisers from measuring conversions. So if you click an ad in Apple News and then buy an app from the App Store they will measure and charge the advertiser for that conversion without ever popping up a scary message saying Apple wants to track you. Go figure.
The companies have worked around these issues by doing stuff like statistical modeling to guess the conversion rate, but this has obvious downsides and makes everything harder, which puts them at a competitive disadvantage vs. vertically-integrated players like Apple and Amazon.
For one thing, the privacy rules only cover sharing data with third parties. They don’t cover Amazon using its own data for product recommendations.
But also, Amazon doesn’t rely on product recommendations in the first place. When I want to purchase something, I usually go to amazon.com and type in exactly what I’m looking for. No need for Amazon to guess. Amazon does make recommendations, but at least in my case they represent a tiny fraction of purchases.
In that way I’m voluntarily contributing to Amazon’s monopoly. I feel bad about that. But I use Amazon anyway because there are no alternatives that offer even a remotely comparable buyer experience.
By virtue of everything sold on Amazon being in the Amazon app the rule in question is kind of moot. The ATT privacy rules don't matter to them because they've already got everything they need to know about you from your habits in their app.
Also, Apple didn’t limit their own advertisers from measuring conversions. So if you click an ad in Apple News and then buy an app from the App Store they will measure and charge the advertiser for that conversion without ever popping up a scary message saying Apple wants to track you. Go figure.
The companies have worked around these issues by doing stuff like statistical modeling to guess the conversion rate, but this has obvious downsides and makes everything harder, which puts them at a competitive disadvantage vs. vertically-integrated players like Apple and Amazon.