What iPhone Duo doesn't have, and what compensates for those losses

The iPhone Duo manages to balance some compromises with unique features that make it a much better option than the iPhone Air. Here's what you don't get in the folding iPhone, and what offsets those losses.
iPhone Duo managed to pull off an ultra-thin foldable design without too many compromises
The iPhone Air created a fork in Apple's lineup that gave users a premium choice that wasn't "pro." However, some users complained that it may have cut too many corners to achieve its thin and light desi