Exactly. For many, the idea of being able to see England, Belgium, Germany, Austria, Yugoslavia, Bulgaria, Turkey, Iran, Afghanistan, Pakistan and India in one 50 day trip with many similar minded travelers who aren't in a rush is really quite appealing.

Also, with bus travel you could, if you felt like it, leave the trip to enjoy many more local attractions and resume your travels later in a way not afforded by airplane or rail travel.