The short version is that if the bounties become too large they'll lose internal talent who can just quit to do the same thing outside the org. Another reason was that they can't offer competitive bounties for zero days because they'll be competing with nation states, effectively a bottomless bank, so price will always go up.
I don't know much about this topic, but surely there are some well structured bounty programs Apple could copy to find a happy middle ground to reward the white hats.
This doesn't compute: is the claim Apple badly manages its bug-bounty because 0-days are too valuable? If that's the case, I'd expect the opposite effect: Apple would recognize how valuable the reports being sent to them by white-hats are, and would react with a sense of urgency and gratitude. As it is, Apple is behaving as if 0-days are worth very little, and not a big priority.
The short version is that if the bounties become too large they'll lose internal talent who can just quit to do the same thing outside the org. Another reason was that they can't offer competitive bounties for zero days because they'll be competing with nation states, effectively a bottomless bank, so price will always go up.
I don't know much about this topic, but surely there are some well structured bounty programs Apple could copy to find a happy middle ground to reward the white hats.