ChatGPT and LLMs in general are an existential threat to Apple.
If you haven't yet, I recommend that you check out plugins for ChatGPT. Companies are now building plugins around ChatGPT so that it can communicate with other services via APIs.
For example, in the future, instead of downloading multiple apps to plan, book your vacation, you can just ask ChatGPT to plan your entire vacation for you. Need to cancel? Just ask ChatGPT to do it. Flight canceled and you're stranded? Ask ChatGPT to call the airline and seek a refund and hotel credits for you.
This greatly diminishes the importance of the iPhone because you will have an extremely fast and capable personal assistant following you around. In the not too far future, you probably just need a screen and an internet connection. It doesn't have to be an iPhone.