Comment The author is ignoring the most obvious answer. (Score 1) 482
The simplest explaination as to why consumers historically tended to prefer buying phones on contract vs putting those same phones on a credit card is that it's often better for both the consumer and the carrier. The carrier benefits by reducing churn (it costs more to acquire a new customer than to keep an existing one) while keeping modern phones in the hands of their customers. The customer benefits because they get access to all the latest infrustructure. In terms of pure cost, it would cost the author about $20/mo to put his Nokia 920 on a credit card and pay it off in 2 years and only $15/mo to buy it on a 2 year contract. He mentions that T-Mobile will let him pay it off at $11/mo but at that rate it would take him 3 years so what's it worth to you to forgo a new phone for an additional year?
So why is this starting to change? Because the improvements in phones are starting to flatten out a bit. The difference between my first smart phone (Moto Droid) and my second one (HTC Rezound) was like night and day but the difference between my Rezound and a HTC One or Samsung S4/5 is not nearly as significant so stretching out the life of the phone an extra year is not nearly as big a sacrifice as it was a few years ago.
BTW his contention that the phone industry is somehow unique is false. The average American has somewhere between $7k and $16k of credit card debt so it's clear that people really ARE borrowing money to buy all sorts of regular consumer products. The reason cellular service providers are willing to loan the money to consumers for a bit less than credit card companies is because the service providers benefit from having customers with the latest gear.