…they already used other versions of ChatGPT.

I doubt very much apple had any say over the personality of GPT-5. And if it did, it’d be in the prompt it sends over to ChatGPT - not in the training and reinforcement part.

Time will tell, time will tell.

Yes, Apple is using another model right now, but, they desperately need an AI win. Thus, they likely want a “latest and greatest model” and they have the leverage to influence what goes into the model. Due to Apple’s previous AI hiccups, performance, safety and guardrails are prioritized, thus a Siri flavored GPT-5.