As you said, too many layers may make it more difficult to move which could be reduced if you could get away with fewer, better quality insulating layers (not to suggest that you have low quality clothes) and that may be what some of these high end brands are trying to offer. However, my city generally experiences winter temps in the -10 to -20C (16 to -4F) range and I am wondering if these high end brands are capable of keeping a cyclist warm in these temps.

On the other hand, it is rare to see an amateur/pro road cyclist (live, photo or video) riding on snow- and ice-packed roads so it might be that high end cycling-specific winter gear (again, Castelli and the like) are designed for winters where the overnight temp might drop to -5C/23F and sunny, daytime temps go up to 5C/41F and any overnight snowfall has melted from the roads in the sun by noon.

I'm interested in hearing whether anyone here owns some of these higher end winter cycling-specific gear and at what temperatures are they comfortable riding in them.