What is the end game here? There is black market for this stuff and payouts are orders of magnitude higher than the bounty programs, why would they skew things even more in favor of that route by behaving like this is a mystery.
This is mostly false except for a narrow class of products and bug classes. You could get more on the black market for an iOS jailbreak than Apple would pay you, yes. You could not get more on the black market for any of the bugs the author submitted - most likely you wouldn't find a buyer at all.