When will US telecommunication company stop subsidizing phones purchase

As the title suggest, when will US telecommunication company stop subsidizing phone purchase.

The reasons iPhone sells so many units is because people are ready to pay $0- $200 to buy a new phone instead of paying $450-$650 for an unlocked phone.This the main reasons iPhone sell a lot in US rather than in Europe. The sales of iPhone in the developing is hopelessly bad.

I really like what T-Mobile is trying to do by stopping subsidizing phone purchase. But I don't think AT&T and Verizon are going to follow suit. I seriously think the laws should be passed to stop this practise

By stopping subsidizing the cost of mobile service like unlimited calling and messaging, would reduce a lot. Data Charges would also reduce as Verizon and AT&T will not have to pay huge amount of money to Apple.

Even though Samsung S III is not as popular as iPhone in US, it sells more units outside US. As people prefer to get their money's worth when buying an unlocked phone.