re: Why doesn't our offense ever point out blocking assignments

That isn't entirely accurate. You still identify the zone blocking schemes presnap, and who/where the mike is plays an important role in that.

ETA: by zone blocking schemes, i mean that you usually have tandem blocks. Two for two. Depending on the d's alignment, that could be a guard/center guard/tackle tandem, and then identifying which two bodies you are responsible for presnap.