Honest question, do you have a source for that? Is it conceivable that Microsoft has some clause that grants them direct access to IP if OpenAI does not meet certain requirements. It is difficult to believe that Microsoft handed over $10B without any safeguards in place. Surely they did their due diligence on OpenAI's corporate structure.
Microsoft has a lot of experience interacting with small companies, including in situations like this one where the small company implodes. The people there know how to protect Microsoft's interests in such scenarios, and they definitely are aware that such things can happen.