That's another question - is MorphOS with a new SMP API, a new ISA and no binary compatibility with 68k Amiga or PPC MorphOS actually MorphOS at all? Or is it another OS by the same developers?
If Amiga OS4 can be Amiga OS, while running on a completely different, utterly incompatible platform to the previous versions, only offering native support to a tiny fraction of Amiga software, I don't see why not.