I guess Google maps might use the IDFA, but photos doesn't have ads and Gmail only works when you're signed in, so a theory that this is related to the IDFA doesn't really hold water.
I would like to correct you here. It doesn't matter if the app is using IDFA or not. If the app is using data for targeting and advertising purposes, they have to disclose that.
Users are always signed into Facebook but they still have to disclose for instance.
Facebook doesn‘t need the IDFA to rack advertising in their own app but they need it to:
- track advertising shown in other apps that use their advertising tools
- use their main app to tie the IDFA (which is all they have from third party apps) to your FB account
Privacy label requirements that some users may look at are one thing, but IDFA access specifically pops up a dialog that can be denied, like location access so it is way more endangered.
But if you're signed in with your google account, they don't need apple to allow them to access an anonymized advertiser id. They have everything they need to track you across iOS and Chrome. The IDFA is completely irrelevant to them here.
Somebody broke something. It's kinda funny for us and embarrassing for Google, but its not a conspiracy
You are applying a technical reason here, but see the bigger picture. Google is being cut off on making money on iOS generally - in web properties, in apps via admob, etc, etc, so may have made a decision that it is no longer supporting it and may be doing so just as leverage. Apple would see the danger that it would drive folks to alternatives that do support Google products.