Since the creation of the App Store, Apple has given back $120 billion in revenue to App Store developers. It means that the App Store has generated more revenue than that in total. But if you remove Apple’s cut, $120 billion have been wired to developers.
App Store revenue is still growing rapidly, as more than $30 billion of developer revenue has been generated in the last 12 months alone. Apple reported $100 billion in developer revenue at WWDC back in June 2018.
Apple only counts direct App Store revenue, such as paid downloads, in-app purchases and subscriptions. Developers also could have generated more revenue through ads and subscriptions on a website, for instance.