Why couldn't you just use OpenAI's API to feed prompts and then take the outputs and use them to train your own model to exfiltrate the best features of GPT?
P.S. this comment does not reflect my personal values. But I would rather someone with values try it almost like a white hat pen test.
"You may not [...] except as permitted through the API, use any automated or programmatic method to extract data or output from the Services, including scraping, web harvesting, or web data extraction;"