Original lineups are hard, albeit not impossible, to find, especially with bands that have been around for a significant time, natural attrition, as mentioned in this very thread, is unavoidable, at least eventually. When it comes to Pink Floyd, there are those who bemoaned the lack of Syd Barrett, for ages. The Who is a weird one, as everyone of the original line up brought something special to the sound, the same can be said for Zeppelin, although Jason makes the perfect replacement for his old man. For the ultimate ‘are they the actual band?’ scenario, look no further than Wishbone Ash and the court case that surrounded that debacle.