What is somewhat justifying OpenAI's valuation is that they are still trying for AGI. They are not just working on models that work here and now, they are still approaching "simulating worlds" from all kinds of angles (vision, image generation, video generation, world generation), presumably in hopes that this will at some point coalesce in a model with much better understanding of our world and its agency in it. If this comes to pass OpenAI's value is near unlimited. If it doesn't, its value is at best half what it is today