People who create awesome content can save themselves a couple years and a lot of money, especially as we get more and more multiplatform-oriented. Right now the Unreal engine runs on Windows. It runs on Unix. It runs on Linux and Mac, and we're looking at getting it going on certain console systems. You want to put out a Mac version of your game, you've got compatible code already done.
Licensed engines are a shortcut and a hedge.
As 3-D engines themselves become increasingly expensive to design, a few underlying technologies gain critical mass. But even as uber-engines coalesce in the game industry, they are starting to compete in other arenas. In the case of Unreal, that means real estate. Unrealty allows architects and developers to model an existing building or a concept in 3-D, explore it in real time and interact with multiple users on a network. If far-flung financiers want to inspect the layout and disagree about the size of the windows or the carpet colors, they can save themselves some air fare.