In it's 300 plus year history it was only owned by one well known musician and very briefly at that. All the other owners were orphans and gypsies, except for the Chinese lady and it was never implied that she was famous.
I could see it being famous if he had it for a long period of time and gave many concerts but going by the movie he only gave one with the Red Violin.
I thought P.E.T.A. meant People Eating Tasty Animals
Pope was supposedly very famous, not just as a violin virtuoso with an incredible private life, but because his fabulous violin disappeared after his death. All that was known was that it was red and an "old Italian violin". And I'm sure there were contemporary accounts of it's incredible sound.
According to the letters there was quite the passage of time and he probably did give concerts during that time. It was only near the end that he got too depressed to play and stopped writing letters to his absent lover. So he probably gave weekly concerts for months.
Nothing like a mystery. It's like finding a lost Da Vinci or Fabergé Egg.