Newell says there isn't just one thing Valve can to do convince EA that Steam is a good place to sell its games -- instead, it has to "prove we are creating value on an ongoing basis, whether it's to EA or Ubisoft or whoever." Steam has a whole host of good reasons for EA to use it, says Newell, including "happier customers, a higher quality service, and [EA] will make more money if they have their titles on Steam. It's our duty to demonstrate that to them. We don't have a natural right to publish their games."
Newell didn't go into further detail about just how Steam would convince EA to come back, but we hear homemade cupcakes are always a nice option.