You can’t eat cake and have it too.
If Anthropic doesn’t own all stock they owe others they’ll have to buy it in the market. If it’s overvalued they’ll have to buy it at a price that will result in losses. If it’s not going to be overvalued then that means that anyone who buys into Anthropic on or after IPO is losing money. Not a good value proposition for buying Anthropic stock, no? And then there’s that $900bn of non-cancellable commitments.