A ridiculous statistic. The emperor has no clothes.
Aprilia comes to that number of "world championship" as a combination of "(grand prix motorcycle racing, Superbike and Off-road)"
Now look at and just consider the competition in the arena of grand prix, superbike and off road....
For example,
Just in motorcycle grand prix, Honda vs Aprilia championships
Honda 63
Aprilia 19.
How about AMA motocross championships
Honda - lots and lots
Kawasaki - lots and lots
Yamaha 19
Suzuki 19
Aprilia 0
World motocross championships
Take your pick of major Japanese and KTM - many
Aprilia 0
WSB championships
Ducati 17
Honda 4
Aprilia 4
Others, 1 or less
Suddenly, Aprilia doesn't look so awesome in the overall context of combined superbike, grand prix and off road championships. And in fact most manufacturers will have Aprilia handily beat in total championships of those combined classes and that total number. Not surprising if you actually look into the details.
And most of Aprilia's success in grand prix motorcycle racing was 125 and 250 cc two stroke motorcycles. Not much bearing on North American bikes and current offerings at all. Just saying....