Apps can offer in app purchases (that's a feature), and they prompt you for your approval and password when you install something that costs. There are also parental controls to further restrict this. To complaint about this is like letting your 6 year old drive your car and complain that he wrecked it like it's the car company's fault.
Also, why you'd even attempt to find "apps that supposedly block ads" is beyond me. Have you even read anywhere that those work with iOS? Apps are in frigging sandboxes.
Plus, those apps CHOSE to be offered for free WITH ads. It wouldn't be ethical to the developer to take ads off of those apps in the first place, even if you could. Sounds like a totally cheapskate-y move.
As for "games that crash all the time" you do know that there are tons of quality titles for iOS right, even for huge companies like EA? You don't have to download every el cheapo (or "free with ads" you'll then try to block) game and then complaint. If one cannot trust oneself to access an app before buying, there are review sites. Thousands of those. Plus user ratings on the app store itself and lists of top and recommended apps.
>I suspect this is the case for a chunk of that $10B.
A very small chunk, and I doubt a chunk that has anything to do with any hacker proper.