Apple's ultra-thin iPhone flops as foldable iPad hits a crease

Weak demand for iPhone Air and delays to a costly foldable tablet suggest Cupertino's hardware experiments are struggling
Apple's run of hardware experiments appears to be hitting some turbulence: The company's ultra-thin iPhone Air has reportedly failed to catch on with buyers, while its long-awaited foldable iPad is slipping further down the calendar amid engineering snags and soaring costs.…