*releases balloons* congratulations, youre the billionth person to wonder why there's no stairway!
Led Zepplin does not want to allow that kind of access to their master tracks. Thats why you dont see them on karaoke machines or juke boxes. Prince is the same way.
The only way you'll see any Led Zepplin on any game anytime soon is when Page AND Plant die (Jones is a *shrug*). Course, if Robert Plant continues to write and create, putting out stuff with Alison Krause, thats a sacrifice im willing to make. Yeah, getting more Blink-182 is no substitute, but somewhere along the line we're going to be getting a whole slew of songs that everybody and his brother will buy twice.