An interesting variation is why we have a general service medal. In the Army/RAF there was one before 1962 and one after 1962 with many different bars added to them. It would have been logical to continue with the GSM for Sierra Leone etc.
The Falklands would appear to be the first of the new medals, and well deserved at that, followed by the GW1 medal. From then we see a raft of NATO, UN, and then OSM issued which mark our change of military from largely stand-alone to a coalition partner.
Will the GSM series ever be resumed or will it eventually fade away?