My interpretation is a little more simple and superficial. Most people in the world think that Rolex is the best without knowing anything about watches. It would make sense to me IF statistics showed that, of all the people who are interested in Rolex, most of them were owners. I believe that Patek is a similar phenomenon... here, we would be talking about more refined people. Of these people, many think that Patek is best. Therefore, it makes sense to me that more of the followers would be owners. I believe that thought process is "why buy anything other than the best?".
Even though VC is comparable to PP in terms of quality, generally speaking, it doesn't have the aura that Rolex and Patek have. So, I believe that when people buy VC, it's because they did their homework (as opposed to getting sucked into the aura created by the marketing department). Of course, people who do their homework sometimes buy VC, but then again, sometimes they end up buying PP, ALS, AP, etc.
That's just my naive interpretation.
PS: I believe it also shows that Rolex's and Patek's marketing/branding teams are ahead of VC's team.