Americans could save a lot of money if they'd consider prepaid. Their are many options, enough to fit most users needs.
With prepaim byod sim plans, you can have the latest and greatest gadgets while paying half what post-paid users on AT&T or Verizon pays.
Myself I pay $49 for unlimited talk, text and 4GB of HSPA+ data
I get twice the data I used to get on Verizon LTE, at half the price and no worries about overages, I'm just throttled if I use more than 4GB.
Even if you considered my bill entirely data costs, I'm paying 12.25 / GB. I pay Europe and Asia Pacific prices
I think the major barrier to prepaid is knowledge, and lack of standards in the US.
Without knowing what your doing, the phones in the US can be confusing. GSM phones work on AT&T and T-mobile, but you might get stuck on edge if you don't know what bands to look for, and CDMA has carrier lock-ins virtually unbreakable. Though I know their are a few ways around it with certain mvno's and carrier's and now we have different LTE bands.
LTE isn't available on mvno's yet, but one day it will.
and sim locks.
If you can't figure out all of this, or at least know someone who can, your stuck with mostly older inferior phones.