The "One Thing"

In my best Curly from City Slicker impersonation I say it's all about "one thing".
What is that one thing that changes this prized fight?

From USA Today Cable, phone companies duke it out for customers .

At stake: the future of the Living Room, which has come to symbolize the long-anticipated convergence of phone, TV and high-speed Internet. The Bells' embrace of video is good news for consumers, says Dominic Endicott, a consultant with Booz Allen Hamilton.

There is one thing that changes the playing field. Any guesses?

The answer lies in that one paragraph above.