Greed can be counter balanced by liability. It can also be limited by removing market access. For much of American history you couldn’t get a corporate charter for multiple states, you were only allowed to operate within one state. Imagine if Sam Altman was only allowed to serve inference to customers in California and legally prohibited from setting up other companies and running inference in New York, someone else would then set up a competing business in New York. Market access is a choice and people are so used to liberalized commerce that they forget the restrictions that are available and existed in the past.