But how much did the iphone 4 cost? If you pay $800 over 8 years thats $100 dollars a year. This thing only costs $100 every two years.
Nevertheless, no one is forcing Apple to pour their profits into extended support for older models.
If anything, the incentive is to end support sooner and push consumers to trade in their old devices for newer models.
Very few people keep the same phone for ten years; most people upgrade every few years, such that their high-end phone never becomes deemed a low-end unit.
If you're particularly cost-conscious, and don't see the added value of a high-end phone, then buy a low-end phone.