Not only does Apple benefit from a Sprint iPhone but so will Sprint

Sprint to offer Apple’s iPhone 5 alongside AT&T, Verizon – report
[Via AppleInsider]

Apple is expected to start selling the iPhone 5 simultaneously with three of the Big Four mobile operators in the USA, Sprint being reported to join AT&T and Verizon for a mid-October launch.

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Sprint has been losing subscribers. One way to hold them is to have access to the hottest phone around. Offering the iPhone 5 would help staunch the bleeding.

Apple could sell 6 million more phones if this happened and Sprint would be able to hold on to another 6 million subscribers for a couple of years.