As technology advanced, the old had to make way for the new, GPS. With operators using primarily the GNSS (Global Navigation Satellite System, i.e. GPS) to navigate, VORs have become less of a necessity. A large number of VOR stations are scheduled to be decommissioned. However, the FAA is retaining a limited network of VORs, called the During a GNSS disruption, the MON will enable aircraft to navigate through the affected area or to a safe landing at a MON airport without reliance on GNSS.
Sometimes the best technology is the most reliable, when in a dire situation.