Cydia (the gray market app store) generates over a million dollars a year in revenue. The operation of this store, and thus its revenue stream, is entirely dependent on jailbroken iOS devices. Thus, there is a business entity with a existential interest in iOS exploits that are easily available to the iOS using community (i.e. the public). Would Cydia pay a quarter million dollars for an exploit to ensure that their customer base continues to exist? (Disclaimer: I'm not affiliated with Cydia in anyway, that revenue figure is from an ex-Apple employee discussing an informal estimate.)