These are non-OTA updates, so I'm not sure that analysis holds. Note that the Verizon CDMA Galaxy Nexus ("toro") is in a similar position, but that JBQ promised an image would be coming soon.
I think a stronger case can be made that Google lacks an architecture like the desktop distros have where they can update packages independently. Why should, e.g., UI improvements to the shell or bug fixes to the settings app be held back by driver validation for an LTE modem?