I wonder if Facebook will be able to find a way to collect not exactly same amount of data but most of the data it captures atm. Ok, if you like to access to uniq identifier that's going to trigger a confirmation modal but as we all know Facebook doesn't necessarily need to capture all the data from the mobile phone directly with their SDK.

Especially, if the user is logged in app owner can send data to their backend and send it to Facebook from there. Like many of those marketing / analytics companies ask you to do.

For the long term tracking, the app owners can still generate uniq identifier and store on device storage, can't they? I guess the only functionality Facebook or any ad network would lose will be cross-app tracking. But I'm not sure how important is that.

The initial reaction Facebook gave to this was too aggressive and Apple will push back for sure with their own way. We all have bloody cookie confirmation on all websites and people mostly just click ok. Isn't that gonna be the same for the apps? In iOS14 modal asking you for confirmation, is it gonna say "Facebook wants to access idfa?" or "X application wants to access idfa?"