That's the dumb pipe theory. Unfortunately there's just too much incremental revenue they'd be giving up by not messing with phone functions and software. The last thing you as a business owner want is to have a gas station model: One on every corner, selling effectively the same product. The only difference might be price, if you have the stomach to run razor thin margins. There are companies that compete well, but they are the big integrated players who have control over every aspect of the product, like Exxon. Verizon's margins are much higher than an Exxon, and they like it that way.