It's ironic that Sam Altman's background is in YC, because this is the opposite of startup thinking. Instead of scrappy disruption he seems to want massive investment upfront with only vague ideas of what the technology could be used for.
They already know that some of these upcoming model builds are going to require $100MM and possibly even a billion dollars. That is just the compute costs for building a single model. Product-market fit is basically established and the cost structure is basically understood so he needs the money for pretty straighforward reasons.
With that said it's a gamble since somebody might come along with a $10MM model based on some new technique and then OpenAI's cost structure becomes a problem. Presumably their scientists could adapt pretty quickly though if that happened.
