The idea behind AmigaDE is that some day the AmigaOS will run on PCs and handhelds and fruit computers. But in the meantime we need a "meeting place" to regroup and readjust our strategy. That "meeting place" just happened to contain a CHRP motherboard. I think it mainly had to do with having access to PowerPC technology through their existing code base and not having any x86 software available for Amiga at that time.
The AMD k6-II was the recommended platform for development of AmigaDE when it first came out. The x86 development platform got the shaft when the Amiga community rejected AmigaDE.
Hardware DOES have something to do with the selling of AmigaOS but until there is a common software base for AROS, AmigaOS, and MorphOS there is not going to be much left to pick up the pieces of the shattered Amiga community. AmigaDE could have done it but the only chance I see of the Amiga community pulling out of this is if AInc. and Tao Group come out with an Amiga version of AmigaDE and it catches on. Otherwise the best we can come up with for multiplatform compatability is SDL and the Amos Basic spinoffs that are going to use it. :-(