Definitely antiquated
Radio fail procedures are definitely antiquated and, apart from Squawk 7600, are barely understood by pilots and ATCOs.
Always loved the bit about "Delay not determined" which would trigger what the old instructors called "the bog off" procedure.
Also, the old procedural approach courses were fun as aircraft below the assumed level of the radio fail were told to leave the hold as the radio fail was assumed to be descending through their levels!
Time for a rethink by someone somewhere.