That was rumoured by many because of his phenomenal technique and Paganini himself fostered that legend, probably to the rue of the Catholic culture in Italy. But he was heir to that technique via Vivaldi, through the Frenchman Leclair, and into the late Romantic virtuosos like Pablo de Sarasate, the Pole Wieniawski, and into our own century with the violinist-composer Fritz Kriesler. Their techniques were derived from certain finger patterns that are above the discipline of prodiies and intuitives, who play primarily by instinct. They almost always disappear because they have neither the discipline or desire to work at the cerebral and physical side of performance. VERY few top virtuosos were prodigies.
Think NHL hockey players . . . . I know several, and they were not major talents in Junior or PeeWee, but had the desire and discipline. Very few prodigies, like Gretzky, had the desire to work hard and perfect their physical skills. This is the short answer. I have, in my teaching duties, put about a dozen students in professional orchestras, and they are NOT the ones that the soccer moms (they exist in the violin world too, believe me lol) pushed into destructive music festivals.
The difference between a violinist and a fiddler is similar. Very few fiddlers have developed technique. They play by instinct. In the guitar world, think of the "guitar bore" that entertains at parties and Segovia. The gap is that large. There are a few crossovers, but very few. This is the short answer as well.
BTW my good friend (now deceased) and NHL star Greg Polis, was a fine pianist. He was also one of the best checking centers in the league, and won the Rookie of the Year award in the Pittsburgh Penguin's team awards back in the 60's. God rest his soul. Greg was not a major talent in Junior, but wanted it and was tremendously disciplined.
I'll shut up and go away now