Amount of sales matters, the other brands just sell a whole lot more RAM than they do. G.Skill probably sells 10 or 20 sticks for every 1 Patriot sells. I see those more often and thus can have a better idea of how often they are good or bad.
In Raiddinn parlance, that means Patriot has a short track record. Maybe that isn't the best way to describe the situation, but that is just arguing semantics.