Not only are they not releasing Codex (and GPT-3), but in order to get access to the API you have to apply for access and be judged against a proprietary set of criteria that are entirely opaque.
Furthermore, I imagine that if you do any innovative work building on top of Codex (or GPT-3) they would control that work product, they would be able to cut you off from accessing your work product at any time if it suits them, and they would be able to build off of your work themselves, co-opting any unique value that you may create.
Why the hell should anyone building an AI business even want to work with them? Sure, it might accelerate your effort right at the beginning, but if you are unable to reproduce your results outside of their platform, you will always be beholden to them.
In a few years will we be reading stories about unfortunate entrepreneurs who had built their businesses on top of OpenAI only to have the rug pulled out from under them, like Amazon sellers whose product was cloned by Amazon Basics, or Twitter clients cut off from the API, or iOS apps made redundant by their core functionality being copied by Apple, or search-driven businesses circumvented by the information cards that Google displays directly in the search results...? Etc, etc.
Am I missing something here?