Bill Gurley is the president and founder of the P3 Institute, and a former venture capitalist.Two of the most valuable companies in American artificial intelligence, Anthropic and OpenAI, are preparing to go public at valuations near $1 trillion — valuations that rest on the promise of extraordinary profit margins. The fastest-growing challenge to those margins is not another well-funded AI lab. It is a wave of powerful AI models being given away for free. The newest of them was released in Chin...