Right. But why have the "pro" line if the phones aren't equivalent? I'm sure there's probably some opaque reason why the smaller size can't have the 5x optical zoom as well but I still think it's dumb.

I want the Pro version. I want all of the features, but not the Max size. But that phone doesn't exist for some reason. I want to believe it's a practical limitation, but my guess is the main reason is to up sell.

As the person you responded to just stated, the reason is the physical size of the device itself. Apple has done this before before w/ the 12 pro vs. pro max.

It shouldn't be any more opaque than why the larger device also has a larger battery. Optical zoom requires additional physical space for the optics doing the zoom. This doesn't make all smaller device options the basic models it makes them the smaller options of their class.