If that is the case, this is possibly because handling the kind of computational load created by genAI requests is extremely intensive. It takes a lot of computer power to ask ChatGPT for a recipe suggestion, and even some relatively recent devices might not yet be up to the task.
What this means is that to access these services, you will need to be running an iPad or Mac with an M1 chip, or later. These services will also require at least an iPhone 15 series device. I imagine this will spark an upgrade surge as Apple customers seek to try these new services.
In use, Apple is thought to have developed an on-device computational mechanism that will choose whether to process specific tasks on the device or via M2-based servers it is now thought to be putting into place. You’ll be able to opt-in to using these services, and the company will focus on privacy.