> Most user-SW on MOS is Amiga68K.

That's individually different for every MorphOS user, I think. I for one have certainly way more PPC binaries on my system than m68k ones.

> I really doubt that there are so many proggers out there,
> to reemplement SMP-SW or write new from scratch in
> short time (or even long time).

MorphOS already has performance-critical software that could easily make use of hardware threads because it is ported from SMP-aware mainstream code, like WebKit or FFmpeg.

> there are so many different peripherial-chips used - who writes
> the drivers for all of that under MOS? If there will be a
> plattformswitch, then only to some selected hardware

Yes. MorphOS on x64 will only support those x64 boards that have supported chips (or expansion slots for cards with the supported chips), certainly not worse than MorphOS on Power(PC) only supporting those Power(PC) boards that support has explicitly been added for. The MorphOS team has been absolutely clear about this.

> but never to those everday-PCs at you can buy in supermarkets

I wouldn't rule out that MorphOS for x64 may happen to support a board, by chance more or less, that ends up in a supermarket PC and happens to contain supported chips (or expansion slots to use cards with supported chips instead of any unsupported on-board chips).