I find this almost impossible. The culture at both these companies is at polar ends. Apple would have to justify themselves all over again and probably till the end of time if they acquire OpenAI. This was not the case with other acquisitions.
The only reason they have been working with OpenAI’s ChatGPT is because they know they are behind Google and Meta but I am sure they are building on their own LLMs in the background. The end goal will be to launch their own AI servers some day even if that takes a decade.