Twitter had a decade to implement something simple like this and didn't. I assume that there are technical reasons that it's hard to do with their codebase and it's simply not worth the time and money to do so.
Ads come with tracking, so there's probably an issue of trusting all the data that apps would have to send back. Twitter would have to document just how much tracking their ads require, and 3rd party developers could balk at it and cause a stink. OTOH the first party app can track as much as it wants and it'll fly under the radar.
I think there’s a pretty wide delta between tracking that is against App Store rules and tracking that would be controversial when written up on the Twitterific/Tweetbot blogs.
