Sure, Apple's BoM has definitely increased given the pressures on the fabs.

By no analysis remotely at the pace that their MSRP has, however.

The primary reason the price has spiralled is that Apple is running out of new markets, so every product needs to feed the greed to a greatest extent as they increasingly squeeze their existing customers. It's the same reason why there are paid ads in the AppStore, on Apple Maps, and so on. Expect this behaviour to become more obvious.