^
Still, word of mouth bringing people over the threshold of buying or watching or reading something doesn't indicate that if you took a sample of random people and showed them the product, they would judge it positively. It only indicates a vocal reaction, which is also common to fads, fashions, urban legends and conspiracy theories. If a meme spreads, it's because it is fit to its goal of spreading, not because it's particularly true, deep or meaningful.
Plus, by arbitrarily redefining markets, you deprive the sales of any power of indicating quality because you break comparison. The Path did well for a game in the "deep symbolism genre" compared to what else? And let's say that there's another game that sold worse because it was not reviewed on destructoid. Did it sell well in the "deep symbolistic game not reviewed on destructoid" subcategory? Maybe relatively better than The Path in its genre?
Going back to the OP: are KZ2's sales indicative that it appeals a randomly chosen "virgin" gamer less than Halo 3, or did it sell very well in the "not very arcade-y console FPSs with no estabilished prior community" market sector? While I call them mixed and intertwined causes for sales besides intrinsic qualities of the product, you're quite fuzzy in what you sweep under the carpet of market subdivision and what not.
And btw: "people who don't look for much quality" is a very real case. Just as many DVDs are quickly grabbed from the shelves with the goal of keeping the kids busy while you have dinner with friends, there are games that are bought with no real regard for its quality. "I only want something the kids can play next friday at my daughter's birthday party" has been said to clerks all over the world uncountable times.
