If i recall correctly, steams "top sellers" go by most recent and most common purchases.
Sakura angels just came out and a bunch of people bought it. That does not mean its more popular than Civ V like you assume it is. Civ V isnt being bought as much in the same time frame because people are buying the complete pack.
So, like nal said
for someone who complains about the store you know next to nothing about it
