The story here is that Sam wanted to raise a lot more, but could not. Investors almost certainly want to see how the Anthropic IPO plays out before deciding whether to keep showering these companies with money.
Sam raised a $100B in previous round. I think a direct listing ipo would see their valuation go up to $4T, and then they could do some at the market sales as needed.
Valuation wouldn’t hold if public. He couldn’t raise the 30B he wanted. I’m not sure how much runway OpenAI has, but sounds like a similar to Anthropic story with valuation likely if in the public markets declining.