I don't understand your reasoning. If you are a black hat and you can get more money for the bug from the company than from selling it on the black market, why would you sell it on the black market?
That's not what I said. A black hat can still try and sell it to the company, but (1) it won't be through the bug bounty process and (2) they are likely not going to pay "market price", whatever that is.
Because maybe I can report it once to the company and make X amount of money, but if the black market price is X / 2, I can potentially sell it many times and make significantly more than X.
