Lets say an average Android user is worth 100 value units, and you can get lots of uniquely identifying information about them, say 90% of the ideal amount of info, so their effective value to you is 90 value units each (90% of 100).
Uniquely identifiable Apple users info is potentially much more valuable, say 200 value units. However you can only get a very small amount of actionable information about them because they are so hard to track, due to Apple's security and privacy systems. So maybe you can only get 10% of the information you would ideally like to have about them. That makes their actionable value to you only 20 value units each (10% of 200).
This is simply bullshit. So-called “targeted” advertising is a giant scam pulled on non-technical marketers who don’t understand it at all and use “measurements” provided by the ad networks themselves.
Targeted ads don’t actually work in any meaningful sense: https://thecorrespondent.com/100/the-new-dot-com-bubble-is-h...
(Disclosure: I work on ads at Google)
A 20-second googling produces one example: https://www.forbes.com/sites/toddhixon/2014/04/10/what-kind-...
Google around for more.