Apple released IDFA to improve consumer privacy, to avoid advertisers being able to fingerprint iOS devices using Unique Device ID (UDID).
Access to UDID was deprecated in iOS 5 (that's 2011).
It has also given control to consumers since then to opt-out of providing IDFA by default.
In 2019, Mozilla asked Apple to take rotate the IDFA every month.
But Apple has taken it even further, which Mozilla publicly applauded https://foundation.mozilla.org/en/blog/applause-for-apples-i...
Apple is now making IDFA disabled by default and requiring users to enable it if they want to.
> Apple went even further than what Mozilla supporters had asked for when it announced that it will give consumers the option to opt-out of tracking in each app, essentially turning off IDFA and giving millions of consumers more privacy online.