The only one who can answer your question is in Geneva.
But, who are the top performing AD's? Are they the ones who sell the greatest quantity and spend the most with Patek, or the ones who take care of their clients correctly and do the things an AD should? What about demographics, or has the internet and telephone sales eliminated the need for someone close by? How does someone establish a relationship with a dealer 500 miles away and how does the dealer know who he is selling a watch to?
A lot of questions to be sure and at one time, Patek appeared to restrict toll free numbers in ads to give some measure of protection from those dealers with wads of cash compared to the smaller dealers is less metropolitan areas with obviously less financial strength. Ah, those were the days. Long gone now from a company who really seemed not interested in big business and wanted to quietly do their own thing.
As to the grey market dealers and the notion that the collectors are being cheated ... I certainly have my own thoughts but they will be different for everyone based on their own experiences.
Could be the grey market dealers and the auction houses did more to propel their popularity than most of their dealers.