Wouldn't have changed a thing regardless of the level of service (ATC / FIO / Unicom) being provided. There is no low level radar coverage and the only way someone could have perhapes warned the aircraft was off track would have been through the use of a VDF in the tower which gives the bearing. If that device wasn't available (and it wasn't) it wouldn't have mattered if it was ATC FIO or Unicom on.
I don't think he was suggesting that the unicom would have prevented the accident involving the seneca - more that after a short period of time when no aircraft appeared on the runway or there was no call made that the aircraft had commenced the missed approach - that there may be something wrong.