> As other have said, iPhones have an external modem and are fine. Qualcomm insisted on this because they had it, and they're good at marketing.

Addressing the second sentence - I have no knowledge of what transpired but my assumption would be a combination of Apple didn't want to have their SOC's fab'd by Qualcomm for the sake of an integrated modem, and Qualcomm didn't want TSMC fab'ing their modem IP into Apple's SOC's, so the obvious solution was a discrete modem which was a product they could offer.