The last sentence doesn't make that much sense to me though. An agreement with Apple to be the lead AI partner would likely juice the IPO a great deal. The financial details wouldn't matter much for the IPO (as the initial financial commitments are going to be small but the halo effect would be real - I think it would in the market anyway).
I think Anthropic has real commitment to their way of doing things which can cause short term issues (and hurt the IPO). And they seem willing to keep those values rather than just making deals to pump the IPO. As you say Apple also sticks to their way of doing things even if it frustrates their partners.
I think not being the lead partner with Apple may well be good for Anthropic long term. But if all you cared about was the IPO just agreeing to Apple's terms likely would have been the best option.
These SpaceX, Anthropic and Open AI possible IPOs are so extreme it is hard to make judgements about them; so maybe there are Anthropic IPO issues to an Apple agreement that I don't appreciate.