The fact that the iphone would cost $399 instead of $199 is not a valid argument in favor of the ETF lock-in. I'd rather actually own my hardware, instead of what basically amounts to leasing the hardware with a modest down-payment and a hefty penalty if you try and switch carriers or end service.
Just like with cars, some people may find it more advantageous to lease their hardware. Good for them, let them lease and make an ETF part of the agreement... but give us an option to 'buy the car' (or iphone).