As i understand, Linux is under a license (GPL) which explicitly prevents closing the reuse of its code. So it’s all about legal interpretation of “reuse” and so far the GPL stands up against abuses. I suppose that a company specifically targeting the source code for the intend of creating another OS might need to hire more lawyers than developers with far from certain results. But who knows, in a world where billions $ are free as soon as “AI” is mentioned in a business plan.