I think that's a fair question. Fundamentally, they don't need to ask because as Apple apps they already have access to it. It's also possible they don't need it and just identify devices via serial, UUID, or other internal identifiers not exposed to third-parties.
We actually don't know how Apple's ad server works and serves personalized ads in the same way we know how say, GMP or The Trade Desk determine their ad placements and bids, which is somewhat more known because of their programmatic nature.
What we do know from some
code sniffing is that Apple absolutely does collect sensitive behavioural data on usage, amongst other data used to personalize ads like installed apps, location, etc. (Information Apple requires consent for third parties to access to serve ads)
Furthermore, since Apple's ad server doesn't rely on it (again, as far as we know, because they collect data through other methods) they don't need to share it with external vendors to serve the ads because they're operating a full black box ecosystem for their own ads.
(Aside: Apple Classical ads on Twitter and elsewhere seem to target users who don't have the app installed, which implies Apple has some level of device information on installed apps and is uploading that data into the bidstream, implying IDFA knowledge, but I can't confirm that, just surmising.)
The people I've been arguing with seem to be committed to the idea that Apple isn't doing anything wrong here, and focused on the ATT modal as proof that everything Apple was doing is on the up-and-up, which is clearly untrue.
What the "Apple is hypocritical" point and the anit-competitive charges come down to is that Apple has placed safeguards (or barriers, depending on your POV) that impact third-parties, whilst having no barriers for its own ad services. Hiding the option to opt-out in a different place from other opt-outs,
and automatically being opted-in to personalized ads is really, really shady. No other app or publisher gets that privilege.
Its privacy play is long term plan to squeeze potential competitors out (mostly for user acquisition spend, which makes up massive, massive amounts of spend on mobile) before doing a more concerted rollout of its own offerings.
People who don't think Apple has an aggressive and profiteering plan around its ad ambitions would do well to remember they went out and quietly hired Antonio García Martínez, the guy who built Twitter and Facebook's modern ad exchanges.
Until a bunch of employees elsewhere in Apple found out, and he was let go for being a massive liability.
Martinez is not someone you hire if you're not building an ad network, and he's definitely not someone you care about if you actually care about privacy, because his entire career is built on exploiting every drop of data possible.