Let's for the sake of argument that this is true; the price is "baked into" the price of the monthly payment and AT&T is making even more money after the contract ended. Would it make an ounce of financial sense to end such a payment scheme? Is this AT&T being a fair corporation?
Next argument. Anybody?
That is basically how it works(ed). It was a great scheme, until smart phones came along, and people began to upgrade their handset every two years or so. When that started, AT&T (and Verizon, and etc., etc.) lost a reliable, somewhat hidden from the customers perspective, revenue stream, and in order to maintain profit margins are now attempting to separate the cost of the phone from the cost of the phone service while keeping the 'service cost' the same.
In my particular case it's painfully obvious: I'm on a familytalk plan with two lines, 2gb of data/line. I pay $120/month for the service, which includes the cost of the subsidized phone. Now, if I move to a shared plan the cost of the service is $110 with two lines, but without the actual cost of the phones. With the phones, the monthly bill would be around 160 if I wanted to upgrade every 2 years like I do now, which is about a 35% increase.