Maybe they have all had success at roughly the same time is because they got into it very early on before many others and already had some background knowledge of affiliate marketing/online marketing.
its all because people like we visit their blogs...its not they are getting rich its we that are making them rich by making their blogs popular...but by the way johncow is missspelled from chonchow.
problogger is considered one of the pioneer while John Chow is a newcomer when compared to the three. Nevertheless, he has made amazing progress in more than a year and on par with Shoemoney these days.