Medals are no more permanent than world records. If you break a world record you are listed forever on the WR progression, if you win a medal you are listed as a medalist forever. Same thing in my books.
So without looking it up, who were the World Record holders at 5000 and 10000 when Viren got double gold in the 1972 and 1976 Olympics?
That is not my point.
There's only one Olympic champ every four years, a world record might be broken 4 times in a year. Someone might hold a world record for a matter of weeks.