In Asia, you can get free unlocked phones just by signing up a contract. In US, you get free locked phones and you still have to sign the contract. You see th

In Asia, you can get free unlocked phones just by signing up a contract. In US, you get free locked phones and you still have to sign the contract. You see the difference? If you have already signed the contract, why do the carrier still has to lock your phone to its network?