You are assuming he wouldn't steal t from OpenAI. He could have a low level employee steal it, and manage to keep it a secret until AGI is born then he takes over the world.
Many people have betrayed their country to foreign governments in exchange for mere thousands of dollars. It is never safe to rule out the willingness of employees to engage in corporate espionage, even in exchange for truly pitiful rewards. It would be a stupid idea, but that doesn't mean it won't happen.