How long has AT & T been selling the iphone? I bet it's alot longer than overnight.
Problem is AT & T don't want to spend the money. They never have. It's been a famous move of the baby bells for years and even though Sprint is one of the few money hungry corporations not spawned from the Bell monopoly they operate under the same premise.
Sigh.... Upgrades don't happen overnight. AT&T has spent billions of dollars on infrastructure. AT&T is spending many more billions of dollars on infrastructure this year, and will continue to do so in the future. The trade-off between revenue and capex isn't limited to telcos.