Apple's belief in the greatness of their goods is probably easier to understand now that they keep going in circles and see nothing but each other and their own stuff.
And yes, at least the Ultra variants might give you similar inference performance to an RTX 4070, while they don't pay customer prices for their hardware.
The main issue that I see is that this is a single scaling point and rather at the current lower end: I can't see it taking them forward very far or being a smart choice when the hardware and software evolution for ML is so fast.
So are they really so single minded or perhaps desperate to scale their chip production to make it more economical?
In the latter case they could just sell the chips to OEMs doing Linux and Windows hardware.
I see this as a sign of economic pressure more than the smartest way to go.