I want that speculation to be true, but I also don't think that the Air is a stepping stone towards that. The risky parts on a folding phone are the bending screen and the hinge and the software features.

The iPhone Air tests none of those things.

It tests their assembly lines and supply chain by producing 100 million titanium cases.

They did something similar when they transitioned the product line to aluminum.

(As a product, it’s the opposite of what I’d want — worse battery, bigger screen, worse camera, but they’ll certainly sell enough to debug the assembly lines.)