It's so near zero it makes no difference. It is not a noticeable factor in my decision on whether to use it or not for any given task.

The training of a brand new model is expensive, but once the model has been created it's cheap to run. If OpenAI went bankrupt tomorrow and shut down the models it had trained would just be sold off to other companies and they'd run them instead, free from the debt burden that OpenAI accrued from the research and training costs that went into producing them. That's actually a fairly common pattern for first-movers like that, they spend a lot of money blazing the trail and then other companies follow along afterwards and eat their lunch.