Security researcher Rich Mogull:

It should surprise no one that Apple is writing their own playbook for bug bounties. Both bigger, with the largest potential payout I’m aware of, and smaller, focusing on a specific set of vulnerabilities with, for now, a limited number of researchers. Many, including myself, are definitely free to be surprised that Apple is launching a program at all. I never considered it a certainty, nor even necessarily something Apple had to do.