Apparently, owning Rockstar Games turns you into an ass. Why deny credit to people? It costs you nothing to credit people. It's just deranged and self-defeating behavior on management's part.
There's simply no reason to expect someone to stay with your company for their entire career. Not only is that bad for the employee, it's bad for the company. If you want to actively retain people, then actively retain them, don't threaten them with a lack of credit.