Apple sells more iPhone units outside the United States than it does inside. So why is every article about iPhone 5 focused on US networks and technologies that are rarely seen outside that country?
Sorry, you've lost me. How does another carrier offering iPhone decrease the number of potential sales that Apple can make?
Apple's sole aim is to sell as many of these as possible and make as much profit as possible. Do you honestly believe Apple considers users who are "stuck on contract" when they choose to release a new phone? You signed the contract.