My understanding of how this works at the Kennedy Center is that the Artist being honored is typically paid tribute by others influenced by him or her and generally they seem to be of a younger generation than the honoree. Given that Beck is rather more of a contemporary of Zep's and arguably as much as or more of an influence on Page than the other way around, then it would not make sense for Beck to be honoring Zep. That would be kind of like McCartney honoring Badfinger!
OK, this makes sense, the rest of this thread, not so much. JSngry too, in his own way.