It is not about mainstream. Please tell me one architecture that has
been created in the last 10 years, supports at least 32bit address
space, virtual memory and doesn't support either CAS or LL/SC.
What's that got to do with it?
NetBSD used to be about proper separation between MI and MD so that
multiple architectures can be accommodated. Even if that meant a lot
of hard thinking to find the right line between MI and MD to take
advantage of things like the MP-ready queue instructions bqt pointed
out the VAX has.
This now makes it appear it now is about lazy coding so that the
"mainstream" architecture can be supported and other arches can be
kinda-mostly supported as long as they're close enough to x86_6^Wthe
"mainstream" one.