You are comparing cheaper phones with substantially more expensive ones. For a meaningful comparison we have to compare phones with a similar price but different size.

False and irrelevant. The claim was "Phones kept getting larger and larger because larger phones sold better."

That claim is demonstrably false. Whether attendant facts like adjusting for price point lead to a subtler inference does not change the absolute fact that the proposition is not consistent with reality.

Price can decrease sales even if size increases sales and price and size are correlated. Causation doesn't always imply correlation.

Again, completely irrelevant.

The claim is "larger phones sold better."

That claim is flatly, objectively false.

I meant of course larger size causes more sales.