OpenAI seems to me like they are operating with a slightly longer horizon strategy than Anthropic. Going for the IPO is the last resort in my mind. It is what you do to get ahead of deteriorating financial conditions. I don't think Anthropic had a choice at their projected burn rate. Why would we surrender all our cloaks and daggers unless we absolutely have to? The political and regulatory headwinds are not looking favorable for AI companies as of a few days ago.

Going for the IPO collapses a large space of options that are available to the business. The AI business is entirely about data. Anthropic's IPO would generate an incredible amount of data that could be used by its competitors to refine their strategy. Knowing where to allocate capital is perhaps worth more than the capital itself at these scales.

Issue is the deteriorating market conditions are already happening, Anthropic didn’t really get ahead of them, but they might just about be able to get the IPO over the line this year albeit for less than they hoped.

What OpenAI will do if market sentiment around AI really falls apart I’m not sure

They filed a confidential S-1 in May, this fundraise was likely plan B