From TFA:
For Private Cloud Compute specifically, the system is described as underpowered and perhaps more trouble than it’s worth. Updating the software is apparently trickier and takes time, and more fundamentally the chips (believed to comprise right now of modified M2 Ultra processors) are not powerful enough to run the latest frontier models like Gemini, which the new Siri will be based on.
> M2 Ultra processors ... are not powerful enough to run the latest frontier models
The local AI community would strongly disagree with that assessment. They may not be able to run them with low latency for interactive use and this is most likely the real blocker for them, but they will have strong compute per watt compared to nVidia GPU's.