And what's wrong with paying $400 to rent a phone in order to get a new phone the next year? My work and personal life rely heavily on the iPhone, so yes, I would like to have the latest and greatest phone in order to stay on top of my busy life.
Also, any financial savvy person knows: lease depreciating assets, buy appreciating assets. And don't ever be foolish enough to pay cash when there's a 0% APR option available (assuming no major hit to credit). Or even better, a contractual commitment rather than a loan (carrier plans over iPhone Upgrade Program).
Why would I pay $800 now for something that'll be worth $400 the next year? How about I pay $400 for an $800 device over the course of a year (so 0% APR), and use the $400 I didn't spend on an S&P ETF to earn a 3-5% annual rate with the same risk as the American economy? (Actually, depending on your brokerage, you could even invest $760 that first year, and deduct $40 from that account monthly to pay to lease the phone to eek out even more gain).