I think all carriers should be at the price point T-Mobile is at. People I think you are paying too much for your phone and coverage. No wonder we in america are struggling financially.
Except that, when you expand T-Mobile's footprint to be that of AT&T's or Verizon's, the cost increases that much more.
Part of the savings in T-Mobile is a reduced coverage area. If T-Mobile with an equal competitor in terms of coverage, I'd agree that AT&T or Verizon was a waste of money. Also, I don't know if T-Mobile's rates are sustainable over the long term. We will see.
I pay $94 a month on AT&T. That includes AT&T's tethering plan, which I use to work on the go. If I excluded it, I'd be paying $78 a month, which is $1,872 every two years (keep in mind I get a discount on AT&T through my employer, but that's not uncommon and only saves me about $10 a month). Factor in that AT&T subsidizes a new iPhone to the tune of $500 every two years, and what I pay to AT&T is exactly in line with what you're paying to T-Mobile (or on slightly more, if T-Mobile includes tethering by default (not sure if they do)).
If an iPhone 3GS is good for you and T-Mobile's network works, more power to you. Not knocking your choice, but just wanted to point out the difference isn't always as stark as the one in your example.