I see what you are saying about the subsidy, but I don't think that should give them license to abuse or take for granted your needs as a customer for the length of the contract.
The payment of the remainder of the actual subsidy mentioned up thread seems the most fair.
As much as the article complains about the increase, Verizon's policy isn't that terrible. The contract I was in was the price of the remaining months of service *per line*, which came out to be far more.
I think more transparency would help here. That way its more fair to the provider and seems less like a money grab.