I want to say again that I'm not making this point by way of a first-principles derivation of what's going on. I know for a fact that the norm in large bounty programs is to incentivize payouts. I don't know that for sure about Apple's program, but it seems extraordinarily unlikely that they depart from this norm, given the care and ceremony with which they rolled this out (much later than other big tech firms).
None of this is to say that the program is managed perfectly, as has been pointed out elsewhere on the thread. I'm not qualified to have a take on that question.